What can we do if the turbulence viscosity ratio increases to a large number or even reaches the limit?
Tagged: 16, Convergence Problems, fluent, fluid-dynamics, turbulence
January 25, 2023 at 7:16 amFAQParticipant
The possible causes for large turbulent viscosity ratio include: – Bad initial conditions for the turbulence quantities (k and e) – Improper turbulent boundary conditions – Skewed cells If the problem is not caused by bad mesh, then the onset of the phenomena can usually be avoided by: -Turn off solving turbulence equations for the first 100-200 iterations -Turn on turbulence and continue iterations If the problem occurs in the midst of the iteration process, then use the following procedure: – Stop the iteration – Turn off all equations except the turbulence equations – Increase turbulence URFs (k and e) to 1 and iterate for 20-50 iterations – Turn back all equations and reduce the turbulence URFs to 0.5-0.8 and then continue iterations – Repeat the above steps for several times For faster convergence, it might be useful to obtain an initial solution with the standard k-e model before switching to a more advanced turbulence model. Because some turbulent flows are inherently unsteady, verify if the flow has any unsteady behavior and switch to transient calculation if needed.
Introducing Ansys Electronics Desktop on Ansys Cloud
The Watch & Learn video article provides an overview of cloud computing from Electronics Desktop and details the product licenses and subscriptions to ANSYS Cloud Service that are...
How to Create a Reflector for a Center High-Mounted Stop Lamp (CHMSL)
This video article demonstrates how to create a reflector for a center high-mounted stop lamp. Optical Part design in Ansys SPEOS enables the design and validation of multiple...
Introducing the GEKO Turbulence Model in Ansys Fluent
The GEKO (GEneralized K-Omega) turbulence model offers a flexible, robust, general-purpose approach to RANS turbulence modeling. Introducing 2 videos: Part 1 provides background information on the model and a...
Postprocessing on Ansys EnSight
This video demonstrates exporting data from Fluent in EnSight Case Gold format, and it reviews the basic postprocessing capabilities of EnSight.
- ANSYS Fluent: Introduction to the GEKO Turbulence Model Part I
- How can I create a Cell Register from a Cell Zone?
- ANSYS System Coupling: Two Way Fluid Structure Interaction – Part 1
- Delete or Deactivate Zone in Fluent
- Left-handed faces troubleshooting
- Running Python Script from Workbench
- ANSYS Polyflow: Adaptive Meshing Based on Contact
- Check CPU Time in ANSYS FLUENT
- How to overcome the model information incompatible with incoming mesh error?
- Apply Custom Material Properties in Fluent
© 2023 Copyright ANSYS, Inc. All rights reserved.