How to render fluid mesh by velocity?

[jianjaven]

Hello everyone, I have a problem on rendering bifrost surface in maya 2018,this is my render test:

I have the velocity pass and displacement map output by Boss, but how can I render mesh by velocity? It means that the splash which with high velocity will be rendered with no displacement, and the other part of mesh which with low velocity will be rendered with displacement, I just want to render the surface with no thickness, how to cut the mesh in rendering? so I can render the mesh just like this:

or is there any other way to render mesh? I want the splash is rendered with no displacement, and the other part of mesh rendered with displacement, and the mesh will be combined with outside infinite ocean, which can be rendered with the same boss displacement map. This is my RnD:

Can anyone help me? Thanks!