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-   -   Problem in k-eps turbulence code in complex geometry (https://www.cfd-online.com/Forums/main/83343-problem-k-eps-turbulence-code-complex-geometry.html)

 sontukaku December 24, 2010 00:46

Problem in k-eps turbulence code in complex geometry

Dear everyone,
I've written a code for solving turbulent flow problem using k-eps model in complex geometry (boundary-fitted coordinate system). The code when run as a laminar producing acceptable result. But if I run it (in lid-driven cavity problem) for turbulent cases (Re=480000). The result is not correct. I took a rectangular cavity (angle of inclination =90deg) and for the mentioned Re, the program is generating a result what one would get in the middle of a of result that an unsteady code would generates (for the same problem) before it (unsteady code) converges. To be precise,the vortex after generating just below the lid-centre comes to the right wall and remained attached there just below the lid instead of going to the centre of the cavity. I have used high-Re model using wall functions and presently trying to solve the flow field only. The matrix is being solved using line-by-line TDMA technique and scheme is SIMPLE with staggered grids.
Thanks in advance for helping me sorting out the problem.

 harishg December 27, 2010 17:10

Have you checked the literature to ensure that the model you use accurately predicts lid-driven cavity problem? Also ensure that the first grid point is in the log-law region.

 sontukaku December 28, 2010 01:44

k-eps

http://dl.dropbox.com/u/14695550/Books/export.epsYes, the formulation working well for simple geometry both in laminar and turbulent cases. Using same scheme I've written the code for laminar case in complex geometry for lid-driven-inclined-cavity problem and that is working fine for square (angle=90deg) as well as inclined cavity problem. But when I changed it to solve turbulent flow problem it's not producing acceptable result. Although converging but result is wrong.
Y+ is kept in the log layer. The vortex is remained attached to the vertical wallhttp://dl.dropbox.com/u/14695550/Books/export.eps as in the attached fig. May be there is something wrong in the physics. http://dl.dropbox.com/u/14695550/Books/export.eps

Thank you.

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