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

Hey, fluent doesnt work !

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 10, 2004, 08:07
Default Hey, fluent doesnt work !
  #1
Javier
Guest
 
Posts: n/a
Hello: I work with sails, and i use it as parachute. I think in this case all the force over the surface must be from viscous terms ( no too much ciculation arround the sail appear), but when i make a force report the viscous force is very smaller than the pressure force. Does anyone knows why?

Other problem is that the pressure force on the sail and the sail shadow are of the same direction, and i think they must pe opossite.

When this problem appear i put a wall in a down stream inviscid flow, and the Dalambert paradox doesnt appear, There was force!. There are too many things i dont understand. Can anyone help me please?

Thanks

  Reply With Quote

Old   February 10, 2004, 09:55
Default Re: Hey, fluent doesnt work !
  #2
Jonas Larsson
Guest
 
Posts: n/a
On a parachute the pressure force is certainly several orders of magnitude larger than the viscous force... the code seems to be right.

Viscous forces are only dominating in cases where you have symmetric streamlined bodies without any separation. Note that the bodies need to be symmetric also, otherwise viscosity (or numerical viscosity if you use an inviscid solver) will always setup circulation which in turn generates pressure forces.
  Reply With Quote

Old   February 10, 2004, 15:17
Default Re: Hey, fluent doesnt work !
  #3
Javier
Guest
 
Posts: n/a
Too much thanks.

Ive been studing the problem and with your contribution, im afraid i solve the stuff.
  Reply With Quote

Old   March 11, 2004, 10:56
Default Re: Hey, fluent doesnt work !
  #4
yogesh and amit
Guest
 
Posts: n/a
hi, this is because in an inviscid solver, we use numerical viscosity of a very low value. we also encountered this problem while analysing the inviscid flow over airfoils..... we have made a 1d nozzle flow analyser and working on a 2d airfoil analysis code...that gives the Cp curves and Cd,Cl too. we want to know the the best scheme.and some references too.

we are sophomores from india.
  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
Fluent does not work MASOUD FLUENT 4 April 9, 2012 13:23
udf fluent 6.3.26 don't work in fluent 12 enry Fluent UDF and Scheme Programming 16 September 9, 2010 02:44
few quesions on ANSYS ICEMCFD and FLUENT Prakash.Paudel ANSYS 0 August 12, 2010 12:07
ATTENTION! Reliability problems in CFX 5.7 Joseph CFX 14 April 20, 2010 15:45
Fluent does not work on openSUSE 11.0 Stanislav Sviderek FLUENT 1 July 28, 2008 17:21


All times are GMT -4. The time now is 07:13.