[usrL]

Dear All,
I am facing a problem in computing the kinetic energy budget in 2d periodic celluar flow. Where the forcing of NS equation is simply f=fo*(-sin(k0*y),sin(k0*x)), with f0=0.02 and k0=2. I am using icofoam solver and the forcing is given using fv.models(). My problem is that the balance should be -nu<||Grad(u)||^2>+<f*u>=0. I found that the magnitude is fine, but the signs are the same, such that these two terms are summing and not subtracting.
I don't know where the sign of the energy coming from the forcing should be reversed.

Thanks for your help.