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Obtaining fully developed OCF velocity profile

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Old   June 6, 2022, 07:10
Default Obtaining fully developed OCF velocity profile
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Hello

I want to obtain the OCF velocity profile without resolving interphase between air and water, i.e. with only single phase solvers such as pisoFoam/pimpleFoam.

I managed to get max velocity profile as the surface (top boundary) with symmetry bc but I think the obtained velocity profile is not correct as after cetrain height from the bottom wall/bounadry the velocity is constant till the top surface (see the figs attached). The major settings used are as follows:

-RANS Model (kOmegaSST)
-K and Omega are treated as wall at lower bounadary where wallunctions are used for both (for k kqRWallFunction, for omega omegaWallFunction)
-Uniform Mesh grading along depth (yPlus= 150-200).
-Turbulence parameters estimated using wiki provided here corresponding to 4% turbulnece intensity and length scale based on mixing length concept (7% of hyd. dia or water depth) as OpenFOAM code is base on that. Resulted k=9.87e-4, omega=5.83. water velocity is 0.675 m/s and water depth or hyd. dia is 0.14 m.
-periodic bc (cyclic) between front and back plane.
-cyclic bc between inlet and outlet, fvOption is used to drive the flow using PatchMeanFlowVelocity type momentum source.


Any suggestions/cpmments to obtain the correct OCF velocity profile similar to attached figure.

Best Regards
Atul
Attached Images
File Type: jpg Obtained OCF.jpg (46.6 KB, 5 views)
File Type: png Corect OCF.PNG (63.4 KB, 4 views)
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