# Dimensionless numbers

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

 September 5, 2007, 09:25 Dimensionless numbers #1 kuba Guest   Posts: n/a Hi, I have to compare to different flow patterns (gas convection) and as a first shot I chose dimentionless numers like Reynolds number, Grashof number, Rayleigh number. Could anyone help me and tell me how/what should I do in Fluent to get these data or some other ideas to compare two different geometries with different flows! Thank you in advance! Brgds, kuba

 September 5, 2007, 14:49 Re: Dimensionless numbers #2 V. Kumar Guest   Posts: n/a do not fully understand your requirement. I guess you want to set particular values of Re, Gr and Ra for your simulations. There are two ways for this: 1) compute everything in dimensionless form. That is transform your equations so that the coefficients of your governing equations are transformed to dimensionless numbers. Then simply compare the dimensionless equations with the equation in dimensional form. E.g. viscosity will be 1/Re thermal conductivity will be 1/Re Pr, density = 1, Delta T = 1, gravity = Gr/Re^2 and so on. 2) Another way is to fix dimensionless numbers and some properties and calcualte back your bounadry conditions and flow velocity and remaining properties from the definition of the dimensionless numbers. I hope this will help.

 September 6, 2007, 04:48 Re: Dimensionless numbers #3 kuba Guest   Posts: n/a Hi, Thank you for the answer but I thought about calculating these numbers for 2 different systems and then compare and draw some conclusions (what are the differences between them). But how to calculate these numbers in Fluent? Brgds, kuba

 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 Chimuka Main CFD Forum 4 September 23, 2011 08:57 Kees Main CFD Forum 1 April 2, 2008 09:15 kubus FLUENT 0 October 1, 2007 04:33 msrinath80 OpenFOAM Running, Solving & CFD 9 July 22, 2007 02:58 liugx212 OpenFOAM Running, Solving & CFD 3 January 4, 2006 19:07

All times are GMT -4. The time now is 16:24.