https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&feed=atom&action=history AC7-03 - Revision history 2024-03-29T14:20:09Z Revision history for this page on the wiki MediaWiki 1.39.2 https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=44248&oldid=prev Torner: /* Abstract */ 2023-07-14T09:00:39Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 09:00, 14 July 2023</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l15">Line 15:</td> <td colspan="2" class="diff-lineno">Line 15:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally determined pressure heads. Afterwards, the results of both simulation methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES shall be answered.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally determined pressure heads. Afterwards, the results of both simulation methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES shall be answered.</div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">The geometry of the VAD is available at the link: https://unibox.uni-rostock.de/getlink/fi8AE4mYS4kxu8ZY51oxDh/</ins></div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated by the LES at the nominal operation point of the VAD.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated by the LES at the nominal operation point of the VAD.]]</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=42154&oldid=prev Mike: Mike moved page Lib:AC7-03 to AC7-03 over redirect 2023-01-11T10:51:47Z <p>Mike moved page <a href="/w/index.php/Lib:AC7-03" class="mw-redirect" title="Lib:AC7-03">Lib:AC7-03</a> to <a href="/w/index.php/AC7-03" title="AC7-03">AC7-03</a> over redirect</p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <tr class="diff-title" lang="en"> <td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="1" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:51, 11 January 2023</td> </tr><tr><td colspan="2" class="diff-notice" lang="en"><div class="mw-diff-empty">(No difference)</div> </td></tr></table> Mike https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41791&oldid=prev Torner: /* Abstract */ 2022-12-01T12:29:39Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 12:29, 1 December 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l12">Line 12:</td> <td colspan="2" class="diff-lineno">Line 12:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are almost always implanted within the body of the patient and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are almost always implanted within the body of the patient and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow conditions. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations <del style="font-weight: bold; text-decoration: none;">and by combining </del>them <del style="font-weight: bold; text-decoration: none;">with </del>a numerical blood damage prediction model (yielding the hemodynamical parameters <del style="font-weight: bold; text-decoration: none;">is </del>described later).</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow conditions. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations <ins style="font-weight: bold; text-decoration: none;">feeding </ins>them <ins style="font-weight: bold; text-decoration: none;">into </ins>a numerical blood damage prediction model (yielding the hemodynamical parameters <ins style="font-weight: bold; text-decoration: none;">as </ins>described later).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally <del style="font-weight: bold; text-decoration: none;">assessed </del>pressure heads. Afterwards, the results of both <del style="font-weight: bold; text-decoration: none;">simulations </del>methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES shall be answered.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally <ins style="font-weight: bold; text-decoration: none;">determined </ins>pressure heads. Afterwards, the results of both <ins style="font-weight: bold; text-decoration: none;">simulation </ins>methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES shall be answered.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated <del style="font-weight: bold; text-decoration: none;">through </del>the LES at the nominal operation point of the VAD.]]</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated <ins style="font-weight: bold; text-decoration: none;">by </ins>the LES at the nominal operation point of the VAD.]]</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41547&oldid=prev Torner: /* Turbulent Blood Flow in a Ventricular Assist Device */ 2022-11-10T14:42:07Z <p><span dir="auto"><span class="autocomment">Turbulent Blood Flow in a Ventricular Assist Device</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 14:42, 10 November 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l4">Line 4:</td> <td colspan="2" class="diff-lineno">Line 4:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>}}</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>}}</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>__NOTOC__</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>__NOTOC__</div></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>=<del style="font-weight: bold; text-decoration: none;">Turbulent Blood </del>Flow in a Ventricular Assist Device=</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>=Flow in a Ventricular Assist Device <ins style="font-weight: bold; text-decoration: none;">- Pump Performance &amp; Blood Damage Prediction</ins>=</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Application Area 7: Biomedical Flows==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Application Area 7: Biomedical Flows==</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Application Challenge AC7-03===</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>===Application Challenge AC7-03===</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41254&oldid=prev Torner: /* Abstract */ 2022-10-25T11:02:27Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:02, 25 October 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l14">Line 14:</td> <td colspan="2" class="diff-lineno">Line 14:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow conditions. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters is described later).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow conditions. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters is described later).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES .</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES <ins style="font-weight: bold; text-decoration: none;">shall be answered</ins>.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated through the LES at the nominal operation point of the VAD.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated through the LES at the nominal operation point of the VAD.]]</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41253&oldid=prev Torner: /* Abstract */ 2022-10-25T11:01:44Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 11:01, 25 October 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l14">Line 14:</td> <td colspan="2" class="diff-lineno">Line 14:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow conditions. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters is described later).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow conditions. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters is described later).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question <del style="font-weight: bold; text-decoration: none;">shall be answered </del>to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES .</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated through the LES at the nominal operation point of the VAD.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|Instantaneous vortical structures in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion [1]. The shown flow field was simulated through the LES at the nominal operation point of the VAD.]]</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41252&oldid=prev Torner: /* Abstract */ 2022-10-25T10:54:41Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:54, 25 October 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l12">Line 12:</td> <td colspan="2" class="diff-lineno">Line 12:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are almost always implanted within the body of the patient and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are almost always implanted within the body of the patient and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow <del style="font-weight: bold; text-decoration: none;">condition</del>. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters described later).</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow <ins style="font-weight: bold; text-decoration: none;">conditions</ins>. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters <ins style="font-weight: bold; text-decoration: none;">is </ins>described later).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41251&oldid=prev Torner: /* Abstract */ 2022-10-25T10:50:59Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 10:50, 25 October 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l10">Line 10:</td> <td colspan="2" class="diff-lineno">Line 10:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Abstract=</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>=Abstract=</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are <del style="font-weight: bold; text-decoration: none;">mainly </del>implanted within the body of the <del style="font-weight: bold; text-decoration: none;">patients </del>and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are <ins style="font-weight: bold; text-decoration: none;">almost always </ins>implanted within the body of the <ins style="font-weight: bold; text-decoration: none;">patient </ins>and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow condition. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters described later).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow condition. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters described later).</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=41249&oldid=prev Torner: /* Abstract */ 2022-10-25T07:38:36Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 07:38, 25 October 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l12">Line 12:</td> <td colspan="2" class="diff-lineno">Line 12:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are mainly implanted within the body of the patients and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Heart failure is a cardiovascular disease, which affects millions of people worldwide. If the heart failure is too severe, a heart transplantation is the gold standard for treatment. Unfortunately, a significant shortage of donor hearts exists worldwide. A technical solution to overcome this gap between demand and availability are Ventricular Assist Devices (VADs). The VADs are mainly implanted within the body of the patients and assist the weak heart by creating the needed pressure to sufficiently supply the circulatory systems.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range <del style="font-weight: bold; text-decoration: none;">is such that it </del>can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow condition. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters described later).</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>The device must be designed in such a way that the VAD's operating range can maintain the blood flow in the circulatory system. For this purpose, a defined pressure head &lt;math&gt; H &lt;/math&gt;  must be built up at a certain blood flow rate &lt;math&gt; Q &lt;/math&gt;. Whether a VAD design meets these fluid mechanical requirements can be checked by flow simulations in the pre-clinical evaluation. Furthermore, a VAD must be designed for highest hemocompatibility, which means that the blood components in the flow are not damaged due to non-physiological flow condition. This can be checked by analysing the fluid dynamical stresses &lt;math&gt; \tau &lt;/math&gt; through flow simulations and by combining them with a numerical blood damage prediction model (yielding the hemodynamical parameters described later).</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td></tr> </table> Torner https://kbwiki.ercoftac.org/w/index.php?title=AC7-03&diff=40601&oldid=prev Torner: /* Abstract */ 2022-06-03T08:10:40Z <p><span dir="auto"><span class="autocomment">Abstract</span></span></p> <table style="background-color: #fff; color: #202122;" data-mw="interface"> <col class="diff-marker" /> <col class="diff-content" /> <col class="diff-marker" /> <col class="diff-content" /> <tr class="diff-title" lang="en"> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">← Older revision</td> <td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 08:10, 3 June 2022</td> </tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l16">Line 16:</td> <td colspan="2" class="diff-lineno">Line 16:</td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>In this context, the present ERCOFTAC KB Wiki entry examines the flow field in a VAD computed by flow simulations. A highly turbulence-resolving large-eddy simulation (LES) is compared as a reference with an unsteady Reynolds-averaged Navier-Stokes simulation (URANS) using a &lt;math&gt; k &lt;/math&gt;-&lt;math&gt; \omega &lt;/math&gt;-SST turbulence model (standard simulation setup by industry for VAD simulations). First, the performed simulations are validated using the experimentally assessed pressure heads. Afterwards, the results of both simulations methods are compared with respect to the computed fluid mechanical and hemodynamical parameters. In particular, the question shall be answered to what extent URANS can reproduce the fluid mechanical parameters (head, efficiency) and hemodynamical parameters (shear stresses and blood damage predictions) compared to the reference LES.</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|<del style="font-weight: bold; text-decoration: none;">Vortices </del>in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion. The <del style="font-weight: bold; text-decoration: none;">presented </del>flow field was simulated through the LES at the nominal operation point of the VAD.]]</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Abstract figure1.jpg|center|500px|thumb|<ins style="font-weight: bold; text-decoration: none;">Instantaneous vortical structures </ins>in the simulated flow domain of the considered axial VAD. Visualised with the Q-criterion <ins style="font-weight: bold; text-decoration: none;">[1]</ins>. The <ins style="font-weight: bold; text-decoration: none;">shown </ins>flow field was simulated through the LES at the nominal operation point of the VAD.]]</div></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> <tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr> </table> Torner