help on resonant spectra in liquid tank
 

I am modeling liquid sloshing in a cylindrical tank (two phase, air and water) by setting a sin function of acceleration in x-direction for the gravity vector.

I had in mind that by increasing the frequency the water wave elevation would increase up to a peak for a certain frequency and after that frequency it would decrease again. But in my model I'm just getting increase in wave elevation no peak!
can anyone help me please? why is this happening?what should i do?

regards;
hamed

You would have to show some results for us to have any idea of what is going on.