CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > Siemens > STAR-CCM+

Axisymmetric supersonic conical flow

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 8, 2019, 06:27
Default Axisymmetric supersonic conical flow
  #1
New Member
 
Join Date: May 2019
Posts: 1
Rep Power: 0
users is on a distinguished road
Hi

I am trying to model the simple case of axisymmetric flow over a cone but I can't seem to get it to converge. My models are axisymmetric, ideal gas, coupled flow, spalart-allmaras turbulence.

My mesh is:
SimpleConeAxisymmetric_Mesh Scene 3.jpg

The bottom is an axis, the left is velocity inlet, the right is pressure outlet and top is freestream. I have tried a lot of different models and meshes and nothing seems to work. If anyone has tips/advice I would appreciate it.

Thanks in advance
users is offline   Reply With Quote

Old   May 8, 2019, 17:56
Default
  #2
Senior Member
 
Matt
Join Date: Aug 2014
Posts: 776
Rep Power: 12
fluid23 is on a distinguished road
Have you tried mesh refinement to resolve the shock(s)? Just looking at your mesh, it looks like the steep gradients associated with the shock would not jive with the large cell size in the core flow (away from the body).
fluid23 is offline   Reply With Quote

Old   May 10, 2019, 04:54
Default
  #3
Senior Member
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 2,181
Rep Power: 32
flotus1 will become famous soon enoughflotus1 will become famous soon enough
What you could try is using a ramp for the prescribed flow quantities at the boundaries. E.g. if you prescribe a velocity of 1000 m/s at the inlet then ramp it up over a few iterations. Define a field function like this and use it as the inlet velocity

Code:
((${Iteration} < 500) ? (${Iteration}/500.0) * 1000.0 : 1000.0 )
This will ramp up the velocity linearly over 500 iterations. Just an example, I have no idea how many iterations might be needed to get your particular case to run.

Btw: you probably don't need the mesh refinement at the boundaries left, top and right.
What is your Mach number exactly? The mesh refinement region seems to be suitable only for very high Mach numbers, i.e. flows with a very narrow Mach cone.
__________________
Please do not send me CFD-related questions via PM
flotus1 is offline   Reply With Quote

Old   October 16, 2019, 16:34
Default
  #4
New Member
 
P
Join Date: Mar 2019
Posts: 2
Rep Power: 0
macaroni is on a distinguished road
Quote:
Originally Posted by users View Post
Hi

I am trying to model the simple case of axisymmetric flow over a cone but I can't seem to get it to converge. My models are axisymmetric, ideal gas, coupled flow, spalart-allmaras turbulence.

My mesh is:
Attachment 69859

The bottom is an axis, the left is velocity inlet, the right is pressure outlet and top is freestream. I have tried a lot of different models and meshes and nothing seems to work. If anyone has tips/advice I would appreciate it.

Thanks in advance
Do you have code for axisymmetric nozzle? Python or matlab?
macaroni is offline   Reply With Quote

Reply

Tags
axisymmetric, cone, conical, supersonic

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Injection of gas into tube with small holes - Supersonic flow mrsl Main CFD Forum 0 December 5, 2018 07:49
steady compressible axisymmetric isothermal flow of Newtonian fluid in conical tube Ivanjica Main CFD Forum 0 January 11, 2018 16:34
Supersonic Inlet for a Compressible Flow in a Nozzle Daco FLUENT 8 November 8, 2012 04:34
Turning supersonic flow into subsonic Salexv FLUENT 7 September 23, 2012 21:10
supersonic axisymmetric cavity flow jsinha1987 FLUENT 0 August 21, 2012 12:11


All times are GMT -4. The time now is 04:08.