relative velocity
 

hello,
i am working with Ansys CFX but i think the question is quite general..

how can i calculate the relative velocity between air (continuous) flowing over water (continuous) ..i need a mean value that means a difference between the velocity in the air core flow and in the water layer because the velocity (inhomogeneous calculation) at the Void_Level=0.5 is near zero (since there is a jump at the interphase).

Or how can i create a quite good relative difference in order to calcluate wave lengths and growth rate of the expect waves and model then a drops diameter. In all the theroies they are using constant velocities but it is inconvenient in my case: turbulent flows, turbulent velocity profile.


thxx for any ideaaa