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Topics relate to LS-DYNA, Autodyn, Explicit STR and more

How to plot the height of a wave as a function of time using ALE elements.

    • Caleb Wood
      Subscriber

      Hello,

      I have a model which simulates the propagation of ocean waves using the ALE method. The model is working as expected. I am trying to plot the change in water height in the global Z direction at a specified point (in this case the specified point is X = 4 m from the origin) as a function of time but cannot seem to do this. I have tried using NODOUT but haven't had any luck. Any insight on this would be greatly appreciated.

      Thank you.

    • ido
      Ansys Employee

      Hello Caleb,

      There is no exact way to do this, but there is an approximate approach. You can try to define a few (dummy) tracers along the water-air interface, maybe associate them with the AMMGID (ALE multi-material group ID) of water. Some tracers may deviate from this interface positions, but hopefully some may be able to stay there. Their positions will give you the info you need. The commands you can try are *DATABASE_TRACER or *DATABASE_TRACER_ALE. Pls give that a try.

      Ian Do

    • Caleb Wood
      Subscriber

      I will try that. Perhaps you can also answer another question of mine. My generated wave is contacting a rigid plate and I want to plot the contact pressures on the bottom of the plate as a function of time. I have tried several keywords but havn't had any luck. My model is behaving as expected I just can't extract the contact forces. Thank you.

    • ido
      Ansys Employee

      Hello Caleb,

      The commands you may try are (a) *DATABASE_FSI or (b) *DATABASE_FSI_SENSOR. Pls give that a try. 

      (a) can output an "estimated" coupling P averaged over a LAG surface entity - there is no exactly correct value for this because we do not have a "physical law" to guide us. The interaction P are only local, estimated, and instantaneous

      (b) can output the elm P in an ALE elm (fluid/mat) 

      Ian Do

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