Learning Forum

[Shayor]

Could anyone tell me what the problem might be?I am trying to couple my Fluent and Ansys Mecha simulation.However I have been stuck with the problem for a month now.I have run the entire simulation successfully with just the Fluent part removing the "System Coupling" and replacing with just "Deforming".I am doing an FSI simulation with the blood flow in an artery with flexible walls.Please help.

I have attached the error messages below.If you want the details of setup I can provide those too.

N.B:My Fluent simulation results match very nicely with the other data available.So there should not be any mistake with the inner setup or values.

Please provide as many options or steps I can take to solve this.I will try them all.I am very short on time as I have to submit my thesis.Thanks in advance.Hope you are all well.

[Stephen Orlando]

Hi FSI simulations with very soft materials or membranes (like an artery) are prone to numerical instabilities. In 2020R1 we have introduced a stabilization method in System Coupling called the Quasi-Newton Stabilization Algorithm. Note that this has to be used with the new System Coupling GUI or Command Line Interface that is run outside of Workbench. More information here: https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v221/en/sysc_ug/sysc_gen_scservice_dt_supplemental_iqnils.html
The following tutorial, specifically this section: https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v221/en/sysc_tut/sysc_tut_oscplate_export_cfx_setup_export.html, shows how to set up a System Coupling case in Workbench and then export it to the new System Coupling GUI outside of Workbench. The new System Coupling GUI gives you access to more advanced features like Quasi-Newton Stabilization. This tutorial is for CFX and Mechanical, but the same export process, and System Coupling GUI setup process is valid for Fluent and Mechanical cases. https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v221/en/sysc_tut/sysc_tut_oscplate_export_cfx.html
Steve

[Shayor]

Thanks a lot Steve.While I look into it could you also tell me if it has anything to do with how custom materials are used in Fluent and Mechanical.For example I edited "Water" in Engineering Data to the properties of Blood and named it so.Same way the Steel was modified to "Blood Vessel".Also for Fluent I used the normal way of defining a Fluid by just changing its name and density.
So does settings like these cause any problem?