having negative volumes in FSI simulation
 

hi guys
I am working on simulation of heart using two-way FSI in ansys 15.0. I have been faced with negative volume problem in updating mesh in fluent. I am using smoothing and remeshing in dynamic mesh.In smoothing I used diffiusion with cell volume parameter 1. In remeshing I used mesh scale information for minimum and maximum length scales.what should I do to solve this problem.
with regards.