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October 17, 2018, 17:07 |
Unreasonable results using icoFoam
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#1 |
New Member
Join Date: Aug 2018
Posts: 12
Rep Power: 8 |
Hello Foamers;
I have had recently a tough time trying to implement and visualize the flow of a open test section in a closed return wind tunnel. I solved all the problems related to creating the mesh and so on, and since i started using openfoam just lately i still need help. This time, the results that i get, don't make any sense. I expect seeing a small shear layer outside the test section and a smooth flow inside the diffuser, due to the slot and the diffuser collector at the entry. What i get is reverse flow coming from the outlet, and very low velocity in the diffuser that goes to zero, and a loooot of turbulence that goes outside very far from the test section. So my mesh is top view of the test section, It is cut into halfs, because i am considering the other half symmetrical. It has an inlet, which is in my case the end of the nozzle, test section that is 5 feet long and diffuser collector at the start of the diffuser, that is inclining by 7degrees. The diffuser has a slot of 2 inch wide and 1 inch long . The design is 2D since there is no change z direction, and also for time consideration. I chose icoFoam solver for laminar incompressible flow. The slot is infinte in Z direction, which is not in reality (it is very small) but i doubt that this is the problem. I am working with openfoam4 and visualizing my results with paraView. The pictures of my results are attached. Any help to recognize the source of the problem will be so much appreciated, i spent on this so much time. FoamFile { version 2.0; format ascii; class volScalarField; object p; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 2 -2 0 0 0 0]; internalField uniform 0; boundaryField { inlet { type fixedFluxPressure; value uniform 0; gradient uniform 0; } outlet { type totalPressure; p0 uniform 0; value uniform 0; } leftside { type zeroGradient; } righttside { type zeroGradient; } symmetry { type symmetryPlane; } right1 { type cyclic; } left1 { type cyclic; } down1 { type cyclic; } down2 { type cyclic; } slot1 { type cyclic; } slot2 { type cyclic; } left3 { type cyclic; } right3 { type cyclic; } walls { type zeroGradient; } farfield { type zeroGradient; } frontAndBack { type empty; } } // FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSolution; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // solvers { p { solver PCG; preconditioner DIC; tolerance 1e-06; relTol 0.05; } pFinal { $p; relTol 0; } U { solver smoothSolver; smoother symGaussSeidel; tolerance 1e-05; relTol 0; } } PISO { nCorrectors 2; nNonOrthogonalCorrectors 0; pRefCell 0; pRefValue 0; } FoamFile { version 2.0; format ascii; class volVectorField; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { inlet { type fixedValue; value uniform (25 0 0); } outlet { type inletOutlet; inletValue uniform (25 0 0); value uniform (25 0 0); } leftside { type fixedValue; value uniform (0 0 0); } righttside { type fixedValue; value uniform (0 0 0); } symmetry { type symmetryPlane; } right1 { type cyclic; } left1 { type cyclic; } down1 { type cyclic; } down2 { type cyclic; } left3 { type cyclic; } right3 { type cyclic; } slot1 { type cyclic; } slot2 { type cyclic; } walls { type fixedValue; value uniform (0 0 0); } farfield { type inletOutlet; inletValue uniform (0 0 0); value uniform (0 0 0); } frontAndBack { type empty; } } FoamFile { version 2.0; format ascii; class dictionary; location "constant"; object transportProperties; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Transport Newtonian nu [0 2 -1 0 0 0 0] 15.34e-6; FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSchemes; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // ddtSchemes { default Euler; } gradSchemes { default Gauss linear; grad(p) Gauss linear; } divSchemes { default none; div(phi,U) Gauss linear; } laplacianSchemes { default Gauss linear orthogonal; } interpolationSchemes { default linear; } snGradSchemes { default orthogonal; } FoamFile { version 2.0; format ascii; class dictionary; object blockMeshDict; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // convertToMeters 1; vertices ( (0 -0.5 0) //0 (1.19 -0.5 0) (0 0.5 0) //2 (1.19 0.5 0) //3 (0 0.91 0) (1.49 0.91 0) //5 (0 -0.5 0.1) (1.19 -0.5 0.1) (0 0.5 0.1) (1.19 0.5 0.1) //9 (0 0.91 0.1) (1.49 0.91 0.1) //11 (0 0.91 0) (1.49 0.91 0) //13 (0 1.21 0) (1.49 1.21 0) //15 (0 0.91 0.1) (1.49 0.91 0.1) //17 (0 1.21 0.1) // (1.49 1.21 0.1) //19 (1.19 -0.5 0) //20 (1.68 -0.5 0) //21 (1.73 -0.5 0) //22 (2.7 -0.5 0) // 23 (1.19 0.5 0) //24 (1.68 0.5 0) // (1.73 0.5 0) //26 (2.7 0.5 0) //27 (1.49 0.91 0) //28 (1.68 0.88 0) //29 (1.73 0.87 0) // (2.7 0.73 0) //31 (1.19 -0.5 0.1) //32 (1.68 -0.5 0.1) //33 (1.73 -0.5 0.1) //34 (2.7 -0.5 0.1) //35 (1.19 0.5 0.1) //36 (1.68 0.5 0.1) // (1.73 0.5 0.1) // (2.7 0.5 0.1) //39 (1.49 0.91 0.1) //40 (1.68 0.88 0.1) // (1.73 0.87 0.1) // (2.7 0.73 0.1) //43 (1.49 0.91 0) //44 (1.68 0.88 0) // (1.73 0.87 0) // (2.7 0.73 0) //47 (1.49 1.21 0) //48 (1.68 1.21 0) // (1.73 1.21 0) //50 (2.7 1.21 0) //51 (1.49 0.91 0.1) //52 (1.68 0.88 0.1) // (1.73 0.87 0.1) //54 (2.7 0.73 0.1) //55 (1.49 1.21 0.1) //56 (1.68 1.21 0.1) //57 (1.73 1.21 0.1) //58 (2.7 1.21 0.1) //59 ); blocks ( hex (0 1 3 2 6 7 9 8) (20 20 1) simpleGrading (1 1 1) hex (2 3 5 4 8 9 11 10) (20 20 1) simpleGrading (1 1 1) hex (12 13 15 14 16 17 19 18) (20 20 1) simpleGrading (1 1 1) hex (20 21 25 24 32 33 37 36) (20 20 1) simpleGrading (1 1 1) hex (21 22 26 25 33 34 38 37) (3 20 1) simpleGrading (1 1 1) hex (22 23 27 26 34 35 39 38) (20 20 1) simpleGrading (1 1 1) hex (24 25 29 28 36 37 41 40) (20 20 1) simpleGrading (1 1 1) hex (25 26 30 29 37 38 42 41) (3 20 1) simpleGrading (1 1 1) hex (26 27 31 30 38 39 43 42) (20 20 1) simpleGrading (1 1 1) hex (44 45 49 48 52 53 57 56) (10 20 1) simpleGrading (1 1 1) hex (45 46 50 49 53 54 58 57) (3 20 1) simpleGrading (1 1 1) hex (46 47 51 50 54 55 59 58) (20 20 1) simpleGrading (1 1 1) ); edges ( ); boundary ( inlet { type patch; faces ( (12 16 18 14) ); } outlet { type patch; faces ( (47 51 59 55) ); } leftside { type patch; faces ( (2 8 10 4) (0 6 8 2) ); } righttside { type patch; faces ( (27 31 43 39) (23 27 39 35) ); } symmetry { type symmetryPlane; faces ( (14 18 19 15) (48 56 57 49) (49 57 58 50) (50 58 59 51) ); } right1 { type cyclic; neighbourPatch left1; faces ( (44 52 56 48) ); } left1 { type cyclic; neighbourPatch right1; faces ( (13 15 19 17) ); } down1 { type cyclic; neighbourPatch down2; faces ( (12 13 17 16) ); } down2 { type cyclic; neighbourPatch down1; faces ( (4 10 11 5) ); } slot1 { type cyclic; neighbourPatch slot2; faces ( (45 46 54 53) ); } slot2 { type cyclic; neighbourPatch slot1; faces ( (29 41 42 30) ); } left3 { type cyclic; neighbourPatch right3; faces ( (1 3 9 7) ); } right3 { type cyclic; neighbourPatch left3; faces ( (20 32 36 24) ); } walls { type wall; faces ( (24 36 40 28) (28 40 41 29) (30 42 43 31) (44 45 53 52) (46 47 55 54) (3 5 11 9) ); } farfield { type patch; faces ( (0 1 7 6) (20 21 33 32) (21 22 34 33) (22 23 35 34) ); } frontAndBack { type empty; faces ( (0 2 3 1) (2 4 5 3) (6 7 9 8) (8 9 11 10) (12 14 15 13) (16 17 19 18) (20 24 25 21) (21 25 26 22) (22 26 27 23) (24 28 29 25) (25 29 30 26) (26 30 31 27) (32 33 37 36) (33 34 38 37) (34 35 39 38) (36 37 41 40) (37 38 42 41) (38 39 43 42) (44 48 49 45) (45 49 50 46) (46 50 51 47) (52 53 57 56) (53 54 58 57) (54 55 59 58) ); } ); mergePatchPairs ( ); |
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Tags |
#reverseflow #boundary |
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