{"id":233406,"date":"2022-08-22T07:48:03","date_gmt":"2022-08-22T07:48:03","guid":{"rendered":"\/forum\/forums\/topic\/problem-with-partial-overlap-of-solid-and-fluid-domains-in-fsi-simulation\/"},"modified":"2022-08-22T07:48:03","modified_gmt":"2022-08-22T07:48:03","slug":"problem-with-partial-overlap-of-solid-and-fluid-domains-in-fsi-simulation","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/problem-with-partial-overlap-of-solid-and-fluid-domains-in-fsi-simulation\/","title":{"rendered":"Problem with partial overlap of solid and fluid domains in FSI simulation"},"content":{"rendered":"

Hi all,<\/p>\n

For my PhD project on abdominal aortic aneurysms, I’m using Ansys System Coupling, Ansys APDL and Fluent to perform FSI simulations of patient-specific geometries. At the moment, we’re working on obtaining patient-specific inlet velocity profiles to use in the CFD part of the FSI simulation. We want to prescribe this velocity at the inlet of the measured geometry. However, in the solid domain, we need to fix the displacements of the inlet (and outlets) in longitudinal and circumferential direction, which causes some numerical inaccuracies close to the inlet (and outlets). Therefore, we normally extend the patient-specific geometry by a few cm, to reduce the effects of the BCs of the solid domain in the region of interest. <\/p>\n

This leads to a mismatch of solid and fluid inlets. To resolve this, I came up with the following idea (see picture):<\/p>\n

The red part is the patient-specific geometry, whereas the blue part is the extension at the side of the inlet. In my CFD (Fluent) simulation, I’m already able to create separate mesh zones for the red and blue parts. I want to prescribe the (patient-specific) velocity at the inlet of the red part and prescribe the current inlet pressure to the complete extension (blue). The extension can be exclude from the CFD simulation, only the pressure needs to be updated each step (according to the changes in pressure at the inlet). <\/p>\n

<\/p>\n

However, I don’t know how to achieve this. Does anyone have any recommendations on how to handle this problem? Or maybe a different approach to handle the mismatch between the solid and fluid domain?<\/p>\n

I also tried another approach (see picture):<\/p>\n

The real patient-specific geometry is used in the fluid domain and the velocity is prescribed at the inlet. The extended patient-specific geometry is used in the solid domain and is divided into the patient-specific (right) part and the extension (left). At the patient-specific part, a 2-way FSI interaction is prescribed, in which the pressures calculated in the fluid domain are transferred to the solid domain and the calculated displacements in the solid domain are transferred to the fluid domain. The extension is coupled to the inlet of the fluid domain using a 1-way FSI interface, so only the pressure of the fluid domain is transferred to the solid domain, no displacements are transferred. <\/p>\n

However, in this case, no mapping can be performed between the extension and the inlet of the fluid domain, because the meshes aren’t conformal. <\/p>\n

<\/p>\n

Hopefully this post is clear to you, I understand it could be quite confusing ?<\/p>\n

Please let me know if you have a suggestion!?<\/p>\n

 <\/p>\n

Best,<\/p>\n

Judith<\/p>\n","protected":false},"template":"","class_list":["post-233406","topic","type-topic","status-closed","hentry","topic-tag-1-way-fsi","topic-tag-2-way-fsi","topic-tag-ansys-apdl","topic-tag-ansys-fluent","topic-tag-boundary-conditions","topic-tag-mismatch"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t