Hi,
I have a 3D case runnin
Hi,
I have a 3D case running of a sphere(d=1) with Re=50 and I want to determine the drag. I used the following in my controlDict functions ( forces { type forces; functionObjectLibs ("libforces.so"); //Lib to load patches (sphere_GmshSphere); // change to your patch name rhoInf 1.22; //Reference density for fluid CofR (0 0 0); //Origin for moment calculations } forceCoeffs { type forceCoeffs; functionObjectLibs ("libforces.so"); patches (sphere_GmshSphere); //change to your patch name rhoInf 1.22; CofR (0 0 0); liftDir (0 1 0); dragDir (1 0 0); pitchAxis (0 0 0); magUInf 0.000753; lRef 1; Aref 0.785398; } ); and nu nu [0 2 -1 0 0 0 0] 1.5e-05; in transportProperties the problem is now , that my drag is too high(about 7 what should be 1.5). Can someone see the a mistake or shall I blame the Grid ? If someone has a case which gives good results for a laminar flow I would be happy about every input. - Daniel |
hi,
when did simulation on
hi,
when did simulation on an airfoil, i also had too high drag. the distance to toe far boundary edge was 40 times the airfoils chord length. increasing to 100 times the chord length improved it. --> try make the grid around the sphere very huge! and yes, the grid is a very sensitive factor to the results. try not to get too great skewness near the boundary layer. and also refine the mesh behind the sphere. |
All times are GMT -4. The time now is 00:31. |