Fluids

Fluids

Understanding Convergence of Solution

    • usama_1424
      Subscriber

      Hi there,

      I am new to CFD modeling and have been using Ansys for the past week. I am trying to build a 3D single phase steady-state model of my open channel flume. Everything works well and when I run the simulation, I get the following residual plot.

    • Rob
      Ansys Employee
      Have a look in the solver theory to understand how that works. The residuals are an indicator of the level of error in the solver: the smaller the value the better. Go through some of the courses too https://courses.ansys.com/index.php/fluids
      In your case, default convergence is 1e-3 for most residuals, so 1-6 is probably overkill. We also use monitors to assist in judging convergence, these are covered in some of the tutorials (click on Help to access these and the documentation).
    • usama_1424
      Subscriber
      Thanks for replying. Just a quick question. Is there anyway we can continue simulations until specified iterations in run calculation parameters have reached despite the convergence achieved or not?
    • Rob
      Ansys Employee
      Yes. In the Monitors-Residual click on "Advanced" and set the Convergence Criterion to "None". We still monitor (display) the residuals but the solver will run until the set iterations are completed. I often do this for steady runs where I'm about to leave for the night/weekend as I don't want the solver to stop 10-15 minutes after I've gone.


    • usama_1424
      Subscriber
      Thanks a lot.
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