Fluids

Fluids

Divergence error : temperature

    • asg
      Subscriber
      Hello everyone,nI'm new to CFD . I'm working on simulation of pressure oscillations In a solid rocket motor. I have given mass flow rate as inlet condition and pressure outlet with certain wall temperature . After few iterations I'm facing divergence error in amg solver : temperature . I can alter it only by changing URF but does it reduce accuracy of my results. My mesh quality is quite good too.nI have given inlet , wall and outlet temperature the same values. Does this lead to this error.nWhy does this error occurs ?
    • RK
      Ansys Employee
      Hello, nIt is difficult to pin point the source of error with the information you have provided. Reducing the URF's will generally help in convergence. However, sometimes, just changing the URFs will not lead to convergence. You will have to look at the model setup, the solution methods that you are employing to solve the problem, etc. The error basically is telling you the simulation is unstable. n
    • asg
      Subscriber
      Thank you for your reply sir. nI would like to add some points to my question. I have used pressure based , transient solver . nModel : laminar- viscousnSolution method : PISO nSecond order upwind discritization of energy and momentum equation.nn
    • RK
      Ansys Employee
      Start off with first order discretization and then move to second order, this might help. n
    • asg
      Subscriber
      Thank you sir ... I will consider thisn
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