Fluids

Fluids

Unable to use Quasi-Newton stabilization in system coupling

    • jfonken
      Subscriber

      For my PhD project, I'm working on FSI models of abdominal aortic aneurysms using Ansys Fluent and Mechanical. Due to the nature of the physics, the added mass effect often causes my models to become unstable. So far, I've been using Ansys 19.2 and I've been experimenting with under-relaxation factors to stabilize my solution. Last week, I read that a new stabilization method, called the Quasi-Newton stabilization, is available in Ansys 20.1. I've installed Ansys 20.1 to try this new stabilization method in the GUI. However, I haven't been able to find the stabilization option. I've included a screenshot of the GUI lay-out. In the data transfer section, I'm able to define the convergence target, under-relaxation and ramping, but I don't see any options for stabilization.

      Please let me know if you know how to add the stabilization method in the System Coupling GUI. Thanks in advance!

    • Stephen Orlando
      Ansys Employee
      Hi J,nGreat to hear you want to try out the Quasi-Newton Stabilization. This algorithm is only available when running System Coupling outside of Workbench using the new Command Line Interface (CLI) or the new GUI. Please have a look at this tutorial showing how to use the CLI. https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v202/en/sysc_tut/sysc_tut_oscplate_cli_fluent.html. You can find the new GUI in the start menu as shown below.nhttps://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v202/en/sysc_ug/sysc_gen_scservice_dt_supplemental_iqnils.html. If you're using a python file to set up your System Coupling simulation, the following is an example command to turn on stabilization for DataTransfer 1 on CouplingInterface 1nDatamodelRoot().CouplingInterface['CouplingInterface 1'].DataTransfer['DataTransfer 1'].Stabilization.Option = 'Quasi-Newton'nIf you're using the GUI, stabilization is turned on as shown below.nThe command in the first line of the picture below gives an error. It doesn't seem to find the Global Stabilization singleton, although it should be there following the Ansys System Coupling userguide. BTW, I'm using Ansys20.1.nDo you know how to specify the global stabilization settings?nThanks in advance!nn
    • Stephen Orlando
      Ansys Employee
      It looks like the Global Stabilization was only added in 2020R2. Please see the 2021R1 doc. I sent links for the 2020R2 doc.n
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