subroutine kenrgy(u,wkdx,wkdy,wkin,wki,wkj)
c
c  Volume integral of (grad_perp u)**2 = 2.0*kinetic energy?
c  wkdx=volume integral of (d u/dx)**2
c  wkdy=volume integral of (d u/dy)**2
c
      implicit none
      include 'itg.par'
c
      real u(lz,mz,nz,nspecz),du1(lz,mz,nz,nspecz),
     * du2(lz,mz,nz,nspecz),wki(mz,nz),wkj(mz,nz),
     * coef,wx,wy,wkin,wkdx,wkdy
      integer l,m,n,mr
      include 'itg.cmn'
c
      do 2 n=1,nd
      do 2 m=1,md
      mr=mrr(m,n)
      du1(1,m,n,1)=(u(2,m,n,1)-u(1,m,n,1))/(0.5*dr(1))
      du2(1,m,n,1)=mr/y0*u(1,m,n,1)
      du1(ld,m,n,1)=(u(ld,m,n,1)-u(ldb,m,n,1))/(0.5*dr(ld))
      du2(ld,m,n,1)=mr/y0*u(ld,m,n,1)
      do 2 l=2,ldb
      du1(l,m,n,1)=(u(l+1,m,n,1)-u(l-1,m,n,1))/dr(l)
      du2(l,m,n,1)=mr/y0*u(l,m,n,1)
    2 continue
c
c     Note that dr(l)=2.0*dx
c     normalize by delta=pi*y0 in the x-direction
c
      coef=0.25/(pi*y0)
      wkin=0.0
      wkdx=0.0
      wkdy=0.0
c
      do 10 n=1,nd
      do 10 m=1,md
      wki(m,n)=0.0
      wx=0.0
      wy=0.0
      wx=wx+dr(1)*du1(1,m,n,1)*du1(1,m,n,1)*0.5
      wy=wy+dr(1)*du2(1,m,n,1)*du2(1,m,n,1)*0.5
      do 20 l=2,ldb
      wx=wx+dr(l)*du1(l,m,n,1)*du1(l,m,n,1)
      wy=wy+dr(l)*du2(l,m,n,1)*du2(l,m,n,1)
   20 continue
      wx=wx+dr(ld)*du1(ld,m,n,1)*du1(ld,m,n,1)*0.5
      wy=wy+dr(ld)*du2(ld,m,n,1)*du2(ld,m,n,1)*0.5
      wki(m,n)=coef*(wx+wy)
      wkj(m,n)=coef*wx
      wkin=wkin+wki(m,n)
      wkdx=wkdx+coef*wx
      wkdy=wkdy+coef*wy
   10 continue
c
      return
      end