Fluids

Fluids

Ansys Insight: Recommendations for convergence using wet steam model

    • RK
      Ansys Employee
      Mesh should be denser in the region where condensation and shock are occurring and also avoid large jumps in the mesh size. Perform a grid check before setting up the model. nStart with wet steam off, select first order discretization and iterate until flowfiled is partially stabilized or partial convergence is obtained. If convergence is still difficult, try reducing the CFL number. nOnce partial convergence is obtained, turn on wet steam equations and setup monitors to check convergence (eg. Monitor wetness fraction at outlet) and continue the iterations using the first order discretization.nAfter a good convergence (residuals ~ 10^-3), you can turn on the second order for accuracy. If you facing difficulties in convergence, reducing the CFL and under relaxation factors would be beneficial. nIf turbulence viscosity ratio crosses the set limit, switch off the turbulence equations and run the solution. Once the flow is developed, switch on the turbulence equations and continue the simulation. nn
    • Surya Deb
      Ansys Employee
      Thank you . This is very useful information.n
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