CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > CD-adapco

simulate a turbulent flow model

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

Reply
 
LinkBack Thread Tools Display Modes
Old   November 7, 2005, 01:04
Default simulate a turbulent flow model
  #1
lenson
Guest
 
Posts: n/a
here I simulate a circular pipe. It's type is turbulent. But the outcome tells me that the velociy profile of outlet is almost similar to laminar flow(thin). I try to change the parameters like turbulent intensity (2%、5%、10%)& turburlent length (1/10 inlet length) the outcome is also similar to laminar flow velocity profile. But the velocity profile of turbulent pipe flow is fatter. can anyone help me ? need to change another parameters? or others?

  Reply With Quote

Old   November 9, 2005, 05:22
Default Re: simulate a turbulent flow model
  #2
Tushar
Guest
 
Posts: n/a
ensure that the reynolds number allows the turbulent flow. I think higher turbulence intensity may give you turbulent velocity profile.

Secondly corrected turbulence model has to be selected for the given nature of the problem. Also select MARS Differencing Scheme with BLendinf of 0.5. Try to give Pressure, Outlet as boundary conditions. PUt the convergence criterion of around 1e-05.

  Reply With Quote

Old   November 26, 2005, 02:20
Default Re: simulate a turbulent flow model
  #3
DB
Guest
 
Posts: n/a
Most important is RE>2000.

DB
  Reply With Quote

Old   December 27, 2005, 02:27
Default Re: simulate a turbulent flow model
  #4
lenson
Guest
 
Posts: n/a
here I have a option.firstly,I simulate a turbulent pipe flow which Re=2744.when setting boundary conditions.I gave the inlet flow turbulent intensity=0.1 and length=0.01145(1/10 inlet length).the first one model I putted the turbulent intensity and turbulent length only in inlet boundary condition.Secondly,I not only use all the first model settings but adding the initializaiton(Thermophysical models and properity-->liquids and gases-->initialization).after selecting initialization ,I choose the turbulence panel.here I also give the intensity=0.1 and mixing length=0.01145. are the differences between two cases ?? my guessed answer for first case:that is upward fluid affect downward fluid. the second is all the fluid condition is in turbulence in the beginning when simulating. can anyone help me propose the physical meanings for these two case.
  Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to model a turbulent flow over a cylinder? Mahbub FLUENT 13 October 29, 2014 16:56
Unable to get turbulent flow using LES model Tang Jingwei FLUENT 6 March 21, 2009 18:59
Look for applications to simulate a rough wall channel flow with turbulent model xiuying OpenFOAM Running, Solving & CFD 0 September 25, 2007 22:21
Combustion model for turbulent flow James Willie FLUENT 3 February 12, 2006 14:33
Can laminar model simulate flow with Re=20000 Baicang FLUENT 4 November 17, 2005 12:39


All times are GMT -4. The time now is 07:10.