DNS 1-2 Quantification of Resolution

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Computational Details

Quantification of Resolution

Statistical Data

Instantaneous Data

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Quantification of resolution

Mesh resolution

The grid resolution corresponds to uniform $\Delta x^{+}=12.2,\ \Delta z^{+}=6.3$ and ranges from $\Delta y^{+}=0.16$ near the wall (first solution point) to $\Delta y^{+}=4.6$ at the centre of the channel. The near-wall Kolmogorov length scale, $\eta =\left({\bar {\rho }}\nu ^{3}/\epsilon \right)^{1/4}$, in wall units is $\eta ^{+}=1.54$.

Solution verification

The solution accurately captures the near wall and log-law behaviour of averaged streamwise velocity profile as shown in Fig. 2.

Figure 2: Average streamwise velocity, $Re_{\tau }=180$, vs data from Moser et al. (1999)

The turbulent stress profiles agree well with the data from Moser et al.

Figure 3: Average streamwise velocity, $Re_{\tau }=180$, vs data from Moser et al. (1999)

The expected near wall behaviour of turbulent stresses are ${\widetilde {u^{\prime \prime 2}}},{\widetilde {w^{\prime \prime 2}}}\sim y^{2},\ {\widetilde {v^{\prime \prime 2}}}\sim y^{4}$ and ${\widetilde {u^{\prime }v^{\prime }}}\sim y^{3}$. These stresses near the wall from the current set of simulations are shown below.

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  ${\widetilde {u^{\prime \prime }u^{\prime \prime }}}$

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  ${\widetilde {v^{\prime \prime }v^{\prime \prime }}}$

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  ${\widetilde {w^{\prime \prime }w^{\prime \prime }}}$

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  ${\widetilde {u^{\prime \prime }v^{\prime \prime }}}$

One way to verify that the DNS are properly resolved is to examine the residuals of the Reynolds- stress budget equations. These residuals are among the statistical volume data to be provided as described in Statistical Data section.

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Contributed by: Lionel Agostini — Imperial College London

Front Page

Description

Computational Details

Quantification of Resolution

Statistical Data

Instantaneous Data

Storage Format

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