wave tank
 

Any help would be appreciated:

I am using FLUENT to model a regular wave tank with linear theory and dynamic mesh in 2D. I am using a VOF multiphase model (water and air), with transitory regime. The length of the water tank is 200m, from th mobile wall, with 16 m depth. I want to measure the magnitude (amplitude) of the wave at at position x = 20 m from the mobile wall, through of the time, in the free surface (depth= 0m), . How to measure the magnitude (amplitude) in that distance?.