Waves simulation / boundary condition problem
 

Hello,

I try to make a gravity wave simulation.
In a box (with free slip condition on boundary and atmosphere for top) a wave is initialized. So we have water and air, I use interFoam to solve this.
In this case I have a very bad result. Normally the kinetic energy will swing infinitely (in case inviscid), but here, energy initially increases (and it is not normal) and crash after 3 period.

If I try to make cyclic condition on the wall right and left, better result is obtained (a form of kinetic energy initially is good). But after some times (2/3 period) the water level start to increase. And so water is created during our simulation...

Do you have an idea for this two problem ? for cyclic condition and slip condition.