LS Dyna

LS Dyna

Water mesh is compressing and disappearing (ALE)

    • powerteqq
      Subscriber

      Hello everyone.

      I'm modelling rigid structure impacting level ice field with cohesive elements. To simulate buoyancy forces, water is modeled as ALE. Everything works fine except water - it is disappearing in compression by vacuum mesh. For water I use EOS Gruneisen and MAT_NULL. For air I use MAT_VACUUM with low density (1e-12). What is the reason for this I can't understand. Look at the pictures below.

    • powerteqq
      Subscriber
      For now, I use MAT_NULL for water and air and EOS_LINEAR_POLYNOMIAL. I obtained values from some paper (image attached)
      But behavior of water is so weird. Could someone help or suggest parameters for water, air and EOSs?


    • tslavik
      Ansys Employee
      Check the velocity of the surface nodes on the ALE mesh. Non-zero velocity indicates fluid is flowing out of the mesh. Use *BOUNDARY_SPC_SET or *ALE_ESSENTIAL_BOUNDARY to enforce no-flow conditions.
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