3d Airfoil Modelling Problems

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

 March 16, 2006, 07:54 3d Airfoil Modelling Problems #1 Olly Guest   Posts: n/a Hi I'm trying to model a 3d airfoil using fluent but am having problems getting the solution to converge. The times that it has converged there is a negative gauge pressure everywhere except for a small point at the front of the wing. I've modelled the wing in a wing tunnel with the following boundary conditions: Inlet - Velocity inlet set to 40ms Outlet - Outflow All other walls set as Symmetry I'm using the k-epsilon solver, i've tried changing the mesh a few times from coarse to fine but am having no luck an ideas? Thanks

 March 16, 2006, 09:50 Re: 3d Airfoil Modelling Problems #2 Oleksiy Dushyn Guest   Posts: n/a Hi, - you should replace your symmetry doundary conditions by periodic ones; - if you are simulating a static case do not make your mesh too fine otherwise you'll run to another problem with flow stability; regards, Alexey

 March 17, 2006, 10:53 Re: 3d Airfoil Modelling Problems #3 Olly Guest   Posts: n/a Thanks for the reply, I changed the outflow to an outlet pressure and this seems to solve the negative gauge pressure up and down stream of the airfoil. I'm now having problems trying to get it to converge at all. the residual plots just go up and then it doesn't converge, what does this mean? Thanks

 March 17, 2006, 11:44 Re: 3d Airfoil Modelling Problems #4 Oleksiy Dushyn Guest   Posts: n/a As I've wtitten in my last posting if you want to get a good convergence you have to replace your symmetry BC by periodic ones. Good luck

 March 17, 2006, 12:12 Re: 3d Airfoil Modelling Problems #5 Olly Guest   Posts: n/a Thanks again, i have replaced the symmetry bc with periodic ones but with no success. What would cause the residuals to go up? Thanks

 March 17, 2006, 13:55 Re: 3d Airfoil Modelling Problems #6 Oleksiy Dushyn Guest   Posts: n/a What initialization do you use?

 March 17, 2006, 15:26 Re: 3d Airfoil Modelling Problems #7 Olly Guest   Posts: n/a I initalise it from the inlet, is that what you mean?

 March 19, 2006, 16:10 Re: 3d Airfoil Modelling Problems #8 Riaan Guest   Posts: n/a 1) use fmg-initialization 2) reduce your under-relaxation functions 3) does your mesh "CHECK" ok?

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post wlvrn Main CFD Forum 0 August 18, 2010 18:43 AW FLUENT 6 February 26, 2010 23:42 ivan_cozza OpenFOAM Running, Solving & CFD 2 September 17, 2009 05:38 Josh CFX 9 August 18, 2009 11:31 Frank Main CFD Forum 1 April 21, 2008 18:36

All times are GMT -4. The time now is 03:16.