00001 /*======================================================================*/ 00002 00003 // This routine evaluates q(k) (McComb, p61) by summing all wavevectors 00004 // in a k-shell. Then we divide through by the volume of the box 00005 // - to be accurate, by the volume of the ellipsoid enclosing the 00006 // box (assume cells even in each direction). Finally, multiply the 00007 // q(k) values by k^2 to give the full power spectrum E(k). Integrating 00008 // this over the whole range gives the energy in turbulence. 00009 00010 /*======================================================================*/ 00011 00012 #include "calcEk.H" 00013 #include "fft.H" 00014 #include <randomProcesses/Kmesh.H> 00015 #include "kShellIntegration.H" 00016 #include <finiteVolume/volFields.H> 00017 #include <OpenFOAM/graph.H> 00018 00019 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 00020 00021 namespace Foam 00022 { 00023 00024 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 00025 00026 graph calcEk 00027 ( 00028 const volVectorField& U, 00029 const Kmesh& K 00030 ) 00031 { 00032 return kShellIntegration 00033 ( 00034 fft::forwardTransform 00035 ( 00036 ReComplexField(U.internalField()), 00037 K.nn() 00038 ), 00039 K 00040 ); 00041 } 00042 00043 00044 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 00045 00046 } // End namespace Foam 00047 00048 // ************************ vim: set sw=4 sts=4 et: ************************ //
