View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0001757 | OpenFOAM | Bug | public | 2015-06-22 12:46 | 2015-06-29 16:48 |
| Reporter | Assigned To | henry | |||
| Priority | high | Severity | minor | Reproducibility | always |
| Status | closed | Resolution | fixed | ||
| Summary | 0001757: compressible- Smagorinsky does not predict a symmetry muSgs | ||||
| Description | Smagorinsky models every gradient as a turbulence contribution. Meaning there is no difference if the gradient comes from shear layer or comes from acceleration/deceleration. These contributions should be same, regardless the sign of the gradients (whether there is acceleration or deceleration in the flow). But in the OpenFOAM- Implementation it is not. It seams that you should write the "b" as an absolute value to make "muSgs" symmetric. Enclosed I send you two snapshots where you can see this problem. src/turbulenceModels/compressible/LES/Smagorinsky/Smagorinsky.C orginal code: volScalarField k(sqr((-b + sqrt(sqr(b) + 4*a*c))/(2*a))); my solution: volScalarField k(sqr((-|b| + sqrt(sqr(b) + 4*a*c))/(2*a))); | ||||
| Tags | No tags attached. | ||||
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2015-06-22 12:46
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I have reviewed the code and your proposal and I do not understand the need for it or the reasoning. The b in volScalarField k(sqr((-b + sqrt(sqr(b) + 4*a*c))/(2*a))); relates to compressibilty effect: volScalarField b((2.0/3.0)*tr(D)); and is zero in the incompressible limit and does not relate to shear or acceleration or deceleration. Also you would expect that compression will increase k and dilatation decrease it so you would expect the b-term to have a sign. Before making the change you suggest could you provide the detailed analysis which leads to you taking the magnitude of b? |
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Please re-open when you can provide analysis supporting your proposed change. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2015-06-22 12:46 |
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New Issue | |
| 2015-06-22 12:46 |
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File Added: smag.tar | |
| 2015-06-23 12:17 | henry | Note Added: 0004983 | |
| 2015-06-29 16:48 | henry | Note Added: 0005016 | |
| 2015-06-29 16:48 | henry | Status | new => closed |
| 2015-06-29 16:48 | henry | Assigned To | => henry |
| 2015-06-29 16:48 | henry | Resolution | open => fixed |
