AnalysisFunctions.py 文件源码

def kurl(arx,ary,arz, kf, lx=2*np.pi, ly=2*np.pi, lz=2*np.pi):
   kx, ky, kz, km = create_kgrid(*arx.shape, lx=lx, ly=ly, lz=lz)

   #  FOURIER TRANSFORM THE ARRAY
   farx = nf.fftshift(nf.fftn(arx))
   fary = nf.fftshift(nf.fftn(ary))
   farz = nf.fftshift(nf.fftn(arz))

   #  SET VALUES ABOVE kf AS 0+0i
   farx = (np.sign(km - kf) - 1.)/(-2.)*farx
   fary = (np.sign(km - kf) - 1.)/(-2.)*fary
   farz = (np.sign(km - kf) - 1.)/(-2.)*farz

   #  COMPUTE VORTICITY
   axf = eye*(ky*farz-kz*fary)
   ayf = eye*(kz*farx-kx*farz)
   azf = eye*(kx*fary-ky*farx)

   #  BACK TRANSFORM TO REAL SPACE
   wx  = np.real(nf.ifftn(nf.ifftshift(axf)))
   wy  = np.real(nf.ifftn(nf.ifftshift(ayf)))
   wz  = np.real(nf.ifftn(nf.ifftshift(azf)))
   return wx,wy,wz