CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Turbulent Boundary condition, viscosity ratio and length scale

Register Blogs Community New Posts Updated Threads Search

Like Tree22Likes

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 16, 2013, 13:06
Default
  #81
Senior Member
 
Francisco
Join Date: Mar 2012
Location: Spain
Posts: 273
Rep Power: 15
Bollonga is on a distinguished road
Hi, I've made a larger domain and a finer mesh and run the 2D case again but this time full-scale.
I've used k-ep RNG instead of realizable.

Simulation starts well, no need to modify under-relazation factors, but it end up in divergence (picture 1) due to turbulence viscosity ratio (TVR) limited to 1e5 in too many cells.
I've taken a picture of TVR distribution just before divergence (picture 2) so I guess the problem is TVR limitation is reached in that area and then it's transported into the wake. I guess I need an finer mesh in the wake region to solve that, don't I?

I've checked y+ around the plate and it's always under 3 (picture 3).

Static pressure and x-wise velocity are plotted in pictures 4 and 5, they both seem right to me, including the profile distribution for the velocity.

Then I've tried a finer wake mesh but there must be something else wrong because divergence occurs just from the very begining.

Thanks
Bollonga is offline   Reply With Quote

Reply

Tags
3d 2d, flat plate, turbulence models, viscosity limitation


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
Wind turbine simulation Saturn CFX 60 July 17, 2024 06:45
Turbulent viscosity ratio limited to 1.10^5 in boundary layer ingestion loicflouriot FLUENT 0 May 27, 2012 08:31
RPM in Wind Turbine Pankaj CFX 9 November 23, 2009 05:05
Problem of Turbulent Viscosity Ratio Limited David Yang FLUENT 3 June 3, 2002 07:13


All times are GMT -4. The time now is 16:22.