# Grid stretching ratio for different flow regions

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

 May 5, 2006, 05:48 Grid stretching ratio for different flow regions #1 quarkz Guest   Posts: n/a I am still quite new to grid generation. I have been reading a few posts on this forum which states that if the grid stretching ratio is bigger than around 1.2, there 'll be errors. However, must this practise be followed even for region such as far upstream/downstream ie places where the velocity/pressure is more or less constant? Can the ratio be higher e.g. 1.5 or even 2.0? By the way, I am using my own 2D FVM fractional step structured solver.

 May 5, 2006, 08:37 Re: Grid stretching ratio for different flow regio #2 ag Guest   Posts: n/a 1.2 is a rule of thumb, and not a hard and fast rule. Ideally, in regions of strong gradients even 1.2 might be a little high, while in regions of small gradients 1.5 may be perfectly acceptable. Of course, what you'll find is that even sticking to 1.2 will give very large cells after you get any distance away from the body.

 May 10, 2006, 15:12 Re: Grid stretching ratio for different flow regio #3 Bounecer Guest   Posts: n/a I'm using too my own 2D FVM to study incompressible flow about airfoil. I've used SIMPLER algorithm and second order upwind scheem for convective terms. although i've used verry small relaxation parameters (2*10**-2) my code program converge to 10**-4 and diverge again. I don't know if the problem is in the formulation of boundary conditions in numerical domain. If y're agree i'm ready to send more details and discuss further ideas.

 May 22, 2006, 04:38 WANT HELP OF GRID STRETCHING #4 LU XIAOTONG Guest   Posts: n/a I just touch grid generation, and I hope to know the function of logarithm grid. Could you please give me some help? LXT

 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 dpc-buaa Main CFD Forum 0 February 22, 2011 23:24 Phillips Main CFD Forum 2 August 25, 2008 18:01 Tylor Xie Main CFD Forum 0 June 9, 1999 07:33 Ridwan Setiadi Arrizar Main CFD Forum 1 January 30, 1999 18:43 J. Ehrhard Main CFD Forum 1 October 8, 1998 19:47

All times are GMT -4. The time now is 06:08.