mathias
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Hi Thir,rnrn No. If you can change the source code in order to have any size you want. Have a look at our example “”cavity3d””.rnrnRegardsrnMathias
Hallo Thir,rnrn You can change the resultion in the xml-file by changing the parameter “”latticeL”” which is the size of a voxel in meter. In this example we have a square cavity of lenth 1 m. The function “”converter->numNodes(x)”” returns the number of voxels of size “”latticeL”” for x meter. In this example we set “”int N = converter->numNodes();”” which gives us the number of voxels of size “”latticeL”” for 1 meter. Have a look at the other examples e.g. “”cylinder2d”” and our user guid.rnrnMathias
Dear MAT,rnrnit seems not to be difficult to implement a model like “”http://www.math.ualberta.ca/ijnam/Volume-9-2012/No-2-12/2012-02-21.pdf”” into the OpenLB code. Basically, you would just have to cange the definition of the collision step in the classes “”dynamics.*”” starting by copying an existing implementation like “”BGK””. We could include your code in the next release if you are happy to share under GPL2.rnrnMathias
Hi,rnrnI understand. Sorry for confusing you. By doing it the way “”P = (RHO – 1) * (Cs*Cs)”” you obtain “”P=0″” for “”RHO=1″”. If you dont do that scaling, you will get different “”pressure levels”” for different discretisations. Then, with the help of the unit converter you can add any constant “”pressure level”” you want. rnrnMathias
Hi Saida29,rnrn Have a look at the OpenLB examples “”thermal2d”” and “”thermal3d””.rnrnMathias
Dear Atiya,rnrnyou can rn a/ change the stl-file another software like FreeCADrn b/ set the material numbers “”by hand””rn “”blockGeometry.setMaterial(iX, iY, iZ, 2);””rn c/ set the boundary conditions “”by hand”” like in “”cylinder2d””rnrnMathias
Dear Atul,rnrnIt is working like in the example “”cavity2d””:rn””vtkOut.writeData<double>(analysis.getVorticity(), “”vorticity””, (T)1/dt);””rnrnJust change “”Vorticity”” to “”Pressure”” and use the right scaling.rnrnMathias
Dear Randy,rnrnSorry for the late reply. Dividing by rho0 is just doing scaling. You need to do that also for the results you get in OpenLB for which you can use the class UnitConverter. The term -1 comes from the followed implemetation strategy in OpenLB (cf. answer question 1).rnrnMathias
Dear Randy,rnrn1) Why do you do this? Does this yield a more stable or accurate simulation?rnA: Yes indeed, we win one or more order of magnitude for the representation of the distribution function f which leads to more stability and accuracy. This is because f-f^eq is small and will be distributed around zero while f is distributes around f^eq which is not zero.rn2) Why is pressure calculated the way it is (shown below)? Isn’t the equation of staternp = rho/c^2,rnnotrnp = (rho-1)/c^2rnA: Have a look at some standard text books on LBM or “Lattice Boltzmann Model for the Incompressible Navier–Stokes“. In the later paper of He/Lou it is explained very nicely in my opinion. rnrnMathias
Hi,rnrnUnfortunately, we do not have an example code with a three- or more-component flow. However, it should be possible to extent the implementation. rnIf you do so, we will be happy to include your example in our next release.rnrnMathiasrn
Hi,rnrn””mpiCC”” and “”mpi++”” should work since OpenLB is written in C++. “”mpicc”” is for C.rnrnMathias
Dear lucasmr,rnrn Thanks for reporting the bug. If you cange line 359 in “”momentaOnBoundaries.hh”” in “”src/core”” from “”defineRhoU(cell, rho_, u_);”” to “”this->defineRhoU(cell, rho_, u_);”” it should work. rnrnWe will correct this in the next release.rnrnBest regardsrnMathias
Dear saida29,rnrnI am n ot really a Fortan expert. To speed up, can you please indicate the line where the velocity is finally computed, shorten the code and comment it.rnrnMathias
Have a look at: http://dx.doi.org/10.1063/1.1399290 rnrnMathias
Dear Shreyas,rnrn The function “”setOffset”” of “”BlockGeometry”” does not change the matrix itself. You need to create a new “”BlockGeometry”” and copy the data by hand. Yet, it is much easier to use the read function of the “”STLReader”” with an appropriate offset. rnrnMathias