We introduce a finite volume scheme to solve isotropic 3-wave kinetic
equations. We test our numerical solution against theoretical results
concerning the long time behavior of the energy and observe that our solutions
verify the energy cascade phenomenon. To our knowledge, this is the first
numerical scheme that can capture the long time asymptotic behavior of
solutions to isotropic 3-wave kinetic equations, where the energy cascade can
be observed. Our numerical energy cascade rates are in good agreement with
previously obtained theoretical results. The finite volume scheme given here
relies on a new identity, allowing one to reduce the number of terms needed in
the collision operators