spherical balls in water with free surface

Karthick

Hello all

I need to send some 20nos of steel balls inside a U shaped tube containing water upto some level. Above the free surface it is atmospheric air and the balls are released into water just above the free surface. With Discrete phase model, we can simulate only considering water as fluid in entire domain and injecting the steel balls. With multiphase model, we cannot specify the location of the release of balls. So I want to know any alternative or new method of simulating such problem using avaialble methods.

Awaiting for a kind response. with regards Karthick