UFR 3-18 Best Practice Advice: Difference between revisions

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The case studies associated with this UFR all demonstrate good practices, which for fully turbulent 2D boundary-layer separation in an adverse pressure gradient may be summarized as follows;
The case studies associated with this UFR all demonstrate good practices, which for fully turbulent 2D boundary-layer separation in an adverse pressure gradient may be summarized as follows;


<span lang="EN-US"><font face="&quot;Times New Roman&quot;">-<span style="font: 7.0pt &quot;Times New Roman&quot;">         </span></font></span>perform grid dependency studies to eliminate sensitivities due to mesh
* perform grid dependency studies to eliminate sensitivities due to mesh


<span lang="EN-US"><font face="&quot;Times New Roman&quot;">-<span style="font: 7.0pt &quot;Times New Roman&quot;">         </span></font></span>assess the effect of sensitivity to boundary conditions by varying the critical inputs
* assess the effect of sensitivity to boundary conditions by varying the critical inputs


<span lang="EN-US"><font face="&quot;Times New Roman&quot;">-<span style="font: 7.0pt &quot;Times New Roman&quot;">         </span></font></span>use higher order discretisation, especially on momentum
* use higher order discretisation, especially on momentum


<span lang="EN-US"><font face="&quot;Times New Roman&quot;">-<span style="font: 7.0pt &quot;Times New Roman&quot;">         </span></font></span>use low-Reynolds non-linear models to capture the effect of near-wall non-isotropy and flow curvature in adverse pressure gradients. k-ω models predict separation better than the equivalent k-ε models
* use low-Reynolds non-linear models to capture the effect of near-wall non-isotropy and flow curvature in adverse pressure gradients. k-ω models predict separation better than the equivalent k-ε models


<span lang="EN-US"><font face="&quot;Times New Roman&quot;">-<span style="font: 7.0pt &quot;Times New Roman&quot;">         </span></font></span>LES modeling is to be recommended where ever possible
* LES modeling is to be recommended where ever possible


<span lang="EN-US"><font face="&quot;Times New Roman&quot;">-<span style="font: 7.0pt &quot;Times New Roman&quot;">         </span></font></span>The V2F turbulence model demonstrates good near-wall flow predictions, and should be investigated for a wider class of problems to boost confidence in its performance.
* The V2F turbulence model demonstrates good near-wall flow predictions, and should be investigated for a wider class of problems to boost confidence in its performance.


<font size="-2" color="#888888">© copyright ERCOFTAC 2004</font><br />
<font size="-2" color="#888888">© copyright ERCOFTAC 2004</font><br />

Revision as of 12:35, 8 March 2009


Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References




2D Boundary layers with pressure gradients (B)

Underlying Flow Regime 3-18               © copyright ERCOFTAC 2004


Best Practice Advice

Best Practice Advice for the UFR

The case studies associated with this UFR all demonstrate good practices, which for fully turbulent 2D boundary-layer separation in an adverse pressure gradient may be summarized as follows;

  • perform grid dependency studies to eliminate sensitivities due to mesh
  • assess the effect of sensitivity to boundary conditions by varying the critical inputs
  • use higher order discretisation, especially on momentum
  • use low-Reynolds non-linear models to capture the effect of near-wall non-isotropy and flow curvature in adverse pressure gradients. k-ω models predict separation better than the equivalent k-ε models
  • LES modeling is to be recommended where ever possible
  • The V2F turbulence model demonstrates good near-wall flow predictions, and should be investigated for a wider class of problems to boost confidence in its performance.

© copyright ERCOFTAC 2004



Contributors: Fred Mendonca - Computational Dynamics Ltd


Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References