Fluid Modeling by Lagrangian elements

Hi

I want to extract frequencies from a fluid/structure model by ABAQUS, but fluid elements just available in Explicit library, and frequency procedure just put on Abaqus Standard, So I decide to use lagrangian element instead of eulerian for fluid. But I don't know how I can do it,

Has EveryBody a solution to extracting frequencies of fluids instead of what I mentioned?

Thanks in advanced

HM