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mimi February 3, 2008 14:31

Natural convection over a vertical wall
 
Dear All

Im new to computational fluid dynamics.I am trying to study natural convection over a vertical wall with sources of heat along the wall.

the wall is 45 m high with a heat source every 10 m and 5 m wide. I am using gambit to generate the geometry .My question is how do i specify the boundary conditions? do i draw an outer boundary around the wall like a huge box .and if the wall has one side with the heat source how do i specify the other parts of the wall as adiabatic.

I hope it clear enough .Any help would be much appreciated

THanx in advance

phy February 3, 2008 15:04

Re: Natural convection over a vertical wall
 
hi

you can draw a box which walls are 45m. and select a vertical wall in boundary conditions menu and set wall. other walls must be presure inlet.

open mesh file in fluent and set temperature for vertical wall than, set temperaturte (ambient temperature) for presure inlets in boundary conditions menu. You have to use bossinesq approximation in materials menu (for air, beta=0.00343 1/K) and selecet PRESTO and second order at solution control.

Dont forget to use ununiform mesh. finest mesh must be at near the vertical hot wall.


mimi February 3, 2008 16:10

Re: Natural convection over a vertical wall
 
thanx Phy i will try that but i need to ask i mesh the area around the wall not the wall itself ....right or not?

phy February 3, 2008 20:22

Re: Natural convection over a vertical wall
 
I cant understand. but please think in 2D. only draw a box and mesh it. than set boundary conditions.

check this site http://courses.cit.cornell.edu/fluent/plate/index.htm

this is forced convection and horizontal plate, so thera are a velocity inlet. but in your model, this is presure inlet and plate is vertical.

Carlos February 3, 2008 20:57

Re: Natural convection over a vertical wall
 
Hi,

You are interested in the FLUID so yes you mesh the air volume around the wall. Obviously the wall itself is solid so you don't mesh that. When you set up the problem in fluent, you will specify the temperature of the wall and give it a thickness. Hope this helps,

Carlos.

phy February 3, 2008 21:05

Re: Natural convection over a vertical wall
 
yes, it is very obvious. thanks


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