January 25, 2022 at 9:43 pmmmmaada00Subscriber
I am trying to simulate a 2D inviscid external compression intake to study the effect of different back pressures on the position of the normal shock within the intake duct/throat. Using a density based solver.
The boundary conditions are as follows:
- Pressure inlet with inputs signifying Mach 2.2.
- Pressure farfield for the external domain.
- Pressure outlet at the exit of the intake with static pressure applied.
The problem is that the flow at the exit of the intake is still wholly supersonic and therefore FLUENT ignores the pressure outlet BC and no normal shock is formed in the duct. I have attached a screenshot of the result.
How do I solve this issue?
Any help will be greatly appreciated, thanks!January 28, 2022 at 12:24 amRKAnsys EmployeeHello,
Can you please give a brief description of the problem setup? What are looking to achieve using simulation? Thanks!
January 28, 2022 at 3:27 amJanuary 29, 2022 at 12:52 pmmmmaada00SubscriberI am trying to achieve a normal shock across the inlet/throat which will decrease the flow to subsonic conditions in order to compare the pressure recovery of different external compression geometries after the shock system. This normal shock should be achieved by imposing a back pressure at the outlet, however ANSYS is ignoring any condition I impose there - no matter what pressure I set. I believe there may be an issue with the problem initialisation as the flow starts supersonic through the whole domain and therefore the back pressure is ignored? Although when I change inlet conditions to subsonic and set a back pressure, I get reversed flow across the outlet.
The setup is a steady inviscid density based solver with ideal gas law for density. Implicit formulation and second order upwind for the flow. The reference values and solution initialisation are computed from the pressure inlet at Mach 2.2.
An example of what I am trying to achieve is this:
Where the normal shock will change location based on the value of the back pressure ratio.
Thanks for any help!
January 29, 2022 at 2:19 pmMarch 1, 2022 at 11:51 ammmmaada00SubscriberHi
Did you ever manage to solve this issue?
March 1, 2022 at 12:13 pm2587521004SubscriberYes I did. Try use k-w sst mode, make sure wall y+ is lower than 30.
March 3, 2022 at 3:07 pmmmmaada00SubscriberUsing the k-w SST model, a normal shock does form but eventually moves out of the front of the intake rather than sitting across the throat/entry. Did you encounter this issue? How did you fix it?
March 3, 2022 at 3:11 pm2587521004SubscriberI never had that kind of problem. Sounds like you need to reduce the static pressure of pressure outlet.
Viewing 8 reply threads
Ansys Innovation Space
- You must be logged in to reply to this topic.
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.Trending discussions
- 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.Ansys does not support the usage of unauthorized Ansys software. Please visit www.ansys.com to obtain an official distribution.