# Naturla convection in enclosed cavities

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 May 30, 2009, 13:56 Naturla convection in enclosed cavities #1 New Member   Ramazan Join Date: May 2009 Posts: 5 Rep Power: 10 Sponsored Links Please help me urgently ! I have an article to solve in FLUENT program.Problem is that all the equations in article are in dimensionless form.There are no any definite parameters (temp,dimensions,etc). In article Ra varies between 10^2 to 10^6.Question is What parameter can I change to reach 10^2 to 10^6 in fluent.Temperature difference or ?

May 30, 2009, 17:35
#2
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Ahmed
Join Date: Mar 2009
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Quote:
 Originally Posted by Karek Please help me urgently ! I have an article to solve in FLUENT program.Problem is that all the equations in article are in dimensionless form.There are no any definite parameters (temp,dimensions,etc). In article Ra varies between 10^2 to 10^6.Question is What parameter can I change to reach 10^2 to 10^6 in fluent.Temperature difference or ?
That is definitly a very short description, here is a short answer, write down the definition of the Rayleigh number, What could you change? temperature, Beta, nu, alpha or may be the gravity if you are working in the outer space/ high altitude. Who knows, it is up to you
Good Luck

 June 1, 2009, 16:38 Natural convection in cavities-SOLUTION CONTROL #3 New Member   Ramazan Join Date: May 2009 Posts: 5 Rep Power: 10 Please give me an idea ; In Fluent program there is a solution controls menu and I want to enter solution types for pressure ,momentum and energy equations. In article which I try to solve in fluent had given some information about this subject.But it is not clear. Please look at following part tell me the solution controls for pressure ,momentum and energy equations: [IMG]file: 2.2.5. Solution procedure The governing equations, Eqs. (1)–(4), are discretized by the fi- nite volume method (FVM) on non-uniform grid system [34]. The third-order QUICK scheme and the second-order central difference scheme are, respectively, implemented for the convection and diffusion terms. The set of discretized equations for each variable are solved by a line-by-line procedure, combining the tri-diagonal matrix algorithm (TDMA) with the successive over-relaxation iteration (SOR) method. The coupling between velocity and pressure is solved by SIMPLE algorithm [34]. The solution is terminated until the convergence criterion is reached, i.e., the maximal residual of all the governing equations is less than 10^6.

June 1, 2009, 18:46
#4
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Ahmed
Join Date: Mar 2009
Location: NY
Posts: 251
Rep Power: 11
Quote:
 Originally Posted by Karek Please give me an idea ; In Fluent program there is a solution controls menu and I want to enter solution types for pressure ,momentum and energy equations. In article which I try to solve in fluent had given some information about this subject.But it is not clear. Please look at following part tell me the solution controls for pressure ,momentum and energy equations: [IMG]file: 2.2.5. Solution procedure The governing equations, Eqs. (1)–(4), are discretized by the fi- nite volume method (FVM) on non-uniform grid system [34]. The third-order QUICK scheme and the second-order central difference scheme are, respectively, implemented for the convection and diffusion terms. The set of discretized equations for each variable are solved by a line-by-line procedure, combining the tri-diagonal matrix algorithm (TDMA) with the successive over-relaxation iteration (SOR) method. The coupling between velocity and pressure is solved by SIMPLE algorithm [34]. The solution is terminated until the convergence criterion is reached, i.e., the maximal residual of all the governing equations is less than 10^6.
If you are looking for recommendations from the readers of this forum, then you need to start learning the basics of communications.
What recommendations do you expect if you do not explain the problem?
Do you think the readers are sitting by your side and know what you are solving? or do you believe all cavities are the same?
Attach the paper you are talking about, or give an address where we can read it or explain the problem

 June 2, 2009, 06:20 Natural convection in square cavities #5 New Member   Ramazan Join Date: May 2009 Posts: 5 Rep Power: 10 Dear Ahmed, Thank you for help file link is here ; http://rapidshare.com/files/239914181/ANA_ALI__350_MA.pdf.html I try to solve this article with FLUENT.I know the basic rules of this program and I always search the all the subjects which are related with this article before writing.But really ,these problems which I already wrote need help. Please look at my article and give me an idea for my questions.(1.Question :Rayleigh number and 2.Question :solution controls menu )

 June 19, 2009, 16:18 Nu number calculation in Fluent #6 New Member   Ramazan Join Date: May 2009 Posts: 5 Rep Power: 10 Hi all! My study is related with 2D natural convection in a square cavity.I change the location and length of the heat sink-sourse pairs to see flow structure in cavity. I solved in Fluent program, but I dont know where can I obtain surface Nu and average Nu numbers.Is there any command to calculate average and local Nu number in Fluent.

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