die casting, help me

paolo

Hi, I have to simulate a process involving a plunger moving in a "tube" (sleeve) containig liquid metal(magnesium alloy) (0,42 volume fraction) and air for remainig volume fraction. at t=0 the two fluids are at rest. Moving plunger will comunicate the motion to the fluids. I used VOF model for multiphase flow, dynamic mesh for plunger motion and Ke model for turbulence. I used an UDF profile for moving plunger (define_CG_motion) like a rigid body, and I defined the two wall boundaries like a deforming. The problem is 2d. What interest to me is only the shape of the front wawe of metal during the plunger motion to see if air remain in liquid metal during the process, nothing else, no thermal or energetic information interest to me, only the fluido-dynamic. The dynamic mesh work great, I used for preview the mesh motion option, but when the simulation start after few time step, this is the message that I receive: turbulence viscosity limited to viscosity ratio. I forgot, I have defined the outlet of the tube like pressure outlet. Help me please, this simulation is for my thesis. ps: excuse me for my english