Fluids

Fluids

convergence problem for super critical fluid accessed from NIST data base

    • ANKITAPUJAHARI
      Subscriber

      Hello,


      I am using supercritical co2 from NIST database to study natural convection in an enclosure.  I have used density-based solver using implicit formulation and the flux type is Roe-FDS. I am starting the simulation from first order. The convergence rate is very slow. What should be done to increase the convergence rate?


      Thank You. 

    • DrAmine
      Ansys Employee

      Why density based solver? Any reasons for that?


      Smaller time steps could be helpful there. Do not forget to switch on gravity. 


       

    • ANKITAPUJAHARI
      Subscriber

      Density-based solver is because of the dependence of density on both temperature and pressure near supercritical temperature and pressure . I have tried using the pressure-based coupled scheme but the probe values are oscillating. One more thing, when I used constant temperature condition on the cold wall convergence resulted. But after using convective boundary condition the convergence rate is extremely slow. I have used steady-state solver

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