January 21, 2021 at 12:21 amdanbenceSubscriberThis option is available in Rigid Motion and UDF. I have a requirement for excluding the mesh motion in a deforming boundary. As this does not seem to be directly available, is it somehow possible to patch the boundary velocities of the deforming surface to zero ? In a UDF ?nThe reason I want this is because I have a rigid body boundary moving very close and parallel to a stationary surface. I do not wish to expend the cost of tiny cells in order to resolve the gap between the boundaries, so want to approximate the situation by having them touch. I think this is analogous to the approximation of turbomachinery touching the shroud. However, turbomachinery has the luxury of not needing dynamic meshing.n
January 21, 2021 at 10:18 amRobAnsys EmployeePlease post some images on what you're trying to do. n
January 21, 2021 at 1:30 pmYasserSelimaSubscriberDefine wall function and return U+ = 0 .. hopefully this worksn
January 21, 2021 at 1:54 pmdanbenceSubscriberHi,nThere is a diagram.n There is a stationary flat surface and a UDF deforming object scraping along the stationary surface (with a small air gap). I am currently getting this to work with the stationary surface and the small air gap in one static zone and interfacing this to a dynamic zone that has the UDF deforming object. I have to expend many cells resolving the small air gap. However I am not interested in the flow in this gap.n What would be ideal is to have a single zone with the UDF deforming object attached to the stationary surface and the stationary surface is set to “deforming”. However, unless I can somehow exclude mesh motion in boundary conditions for the deforming surface, then the physics will be incorrect (ie the stationary surface will be dragged along with the UDF object)n I believe what I want to do is analogous to approximating a turbomachinery fan by attaching it to the shroud and defining relative motion between the shroud and the fan. In this case the mesh is untouched, but appropriate shear stresses/motions are imparted to the fluid close to the surfaces.n Thanks.nn
January 25, 2021 at 11:15 amdanbenceSubscriberThanks for the suggestion.nWon't a custom wall function just vary the velocity profile relative to the wall velocity ? If so, I can?t see this would help, as it is the wall velocity that I want to set to zero in the absolute reference frame.n Also, I don?t think custom wall functions are available with the turbulence model I have chosen (LES)n n n
January 25, 2021 at 2:25 pmRobAnsys EmployeeWhat's controlling/defining the motion? It may be possible to move the hole where the deforming body is and connect it directly to the stationary surface. If you have heat transfer this may get very messy. Alternatively have a look at overset. n
January 26, 2021 at 12:17 amdanbenceSubscriberHi Rob.nThe motion is controlled by a math function in a DEFINE_GRID_MOTION udf.n I was encouraged when I read up on overset mesh functionality, but that was dashed when I discovered it is not available with LES. n
- You must be logged in to reply to this topic.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.
- Suppress Fluent to open with GUI while performing in journal file
- Floating point exception in Fluent
- What are the differences between CFX and Fluent?
- Heat transfer coefficient
- Getting graph and tabular data from result in workbench mechanical
- Difference between K-epsilon and K-omega Turbulence Model
- The solver failed with a non-zero exit code of : 2
- Time Step Size and Courant Number
- Mesh Interfaces in ANSYS FLUENT
- error: Received signal SIGSEGV
© 2023 Copyright ANSYS, Inc. All rights reserved.