Fluids

Fluids

Floating point exception

    • Claudette95
      Subscriber

      Good evening,


      I'm studying a Wankel engine. I can simulate the right motion but during run calculation "floating point exception error" appears. Can someone explain me the reason?


      Thank you very much. 

    • RK
      Ansys Employee

      Hello, 


      Please refer to the discussion in the following thread on the same problem. Let me know if you have any questions, after reviewing the discussion. 


      https://studentcommunity.ansys.com/thread/error-floating-point-exception-4/?order=all#comment-ac8af474-54c0-4ed6-95f9-ab7c01091440


      Regards, 


      Rahul 

    • Claudette95
      Subscriber

      Good morning, I have the same problem of the attached link but I don't use the Outlet-outflow, I put the inlet pression as unique boundary condition. I share here the picture mesh and the orthogonal quality range.The body can rotate so I use dynamic mesh. 


      Thank you very much.


       


      Regards,


      Claudia


    • RK
      Ansys Employee

       Hello Claudia, 


      There could be many reasons for this error. 1) Improper boundary conditions;  2) Improper solver settings;  3) improper set-up of dynamic mesh. To assist you better, can please share some details like boundary conditions used, overall mesh quality and what kind of dynamic mesh you using? Can you also share your residual plots? 


      As you run your simulation, can you also check if the dynamic mesh deteriorates the mesh quality. 


      Regards,


      Rahul

    • Claudette95
      Subscriber

      Good morning, thank you so much for your availability. Yesterday I imposed different boundary conditions and the rotor started to move without problem but the calculation time is very long. To reduce the error's probability comes I put the time step as 1.e-07. Is it normal? or Do you advice me to reduce the element size?


      Here there are some results. Now the calculation is continuing. I am not sure about the spatial discretization (I put all field in second order) and the correction.  I have used an UDF to create the mass center of rotor motion. In dynamic mesh I have choosen smoothing ,down there are the parameters and for remeshing I put the size 1 instead of 5. The mesh quality seems in all points good. How can I solve the lackages problem? In real situation the stator and rotor are koined by springs and they can move "up and down" to follow the stator properly but here the 3 chambers are linked.


      Thank you in advace.


      Best regards.


      Claudia Staffieri 


       


       Is it right to impose different boundary conditions for example mass flow in inlet?


       


       


      Scaled residuals


       


      Buondary conditions


       


      Velocity


      Pressure


       


      Model


      Mesh motion


       


    • RK
      Ansys Employee

      Hello Claudia, 


      Did you create a report definition of any parameter while running the simulation? 


      Regards,


      Rahul 

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