July 2, 2019 at 11:35 pmsharm2a2Subscriber
Hello, I am simulating flow over hemisphere by using unsteady RANS but at the end no vortex shedding appear. The experimental and LES results showed that vortex shedding or kelvin Helmholtz instability is present for that Reynolds number. Can anybody please explain why URANS ( Unsteady RSM model) is not giving this instability ? Thanks and Regards Amit
July 3, 2019 at 6:15 amDrAmineAnsys Employee
The URANS simulation should produce only the large-scale unsteadiness. If you know the response time or the Strouhal number you can have an etimate for period and you need to resolve that period by not less than 50-60 time steps!
July 3, 2019 at 6:23 amDrAmineAnsys Employee
Moving to Fluids
July 3, 2019 at 11:20 pmsharm2a2SubscriberHello Abenhadj
Thank you for your reply but can you please elaborate. I did not understand “ you need to resolve that period by not less than 50-60 time steps“
Thanks and Regards
July 4, 2019 at 7:16 amDrAmineAnsys Employee
50-60 time steps per period. Period is 1/frequency. Frequency from Strouhal number.
- 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
- The solver failed with a non-zero exit code of : 2
- Difference between K-epsilon and K-omega Turbulence Model
- Time Step Size and Courant Number
- Mesh Interfaces in ANSYS FLUENT
- error in cfd post
© 2023 Copyright ANSYS, Inc. All rights reserved.