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jabe April 13, 2002 19:36

interfced coupled system
Hi everyone. I was assigned to calculate the wind loading on a solar panel Dimensions(56`,26,2) I was told to use CFX55 to find out the wind loading effects on the panel which will be at 90 degres (normal) to the wind loading which is 90 miles/hour. 1- I was told to assume my boundary conditions and explain why I choosed them??

2-I need someone to tell me if it is possible to actually use cfx55 to calculate the wind loading??if so then how??

3-I found out with only windspeed given; I can only get the pressure profile and velocity profile?? can someone please tell me how to interface the coupled system that is air and the structure that is intreduced to the air flow.

4- please, explain to me how can I use the information given to me that is wind speed and panel dimensions to actually find the force acting on the structure. I was told that there must be interfacing between the air and the stucture how would it happen and how can do it??

thanx everyone and bye

jabe (new mexico state U.)

jabe April 13, 2002 19:39

Re: interfaced coupled system
I need to find the wind loading on the STRUCTURE?? that what confused me??

Neale April 13, 2002 23:18

Re: interfced coupled system
Have you built your geometry yet? It might be as easy as creating a B-rep solid of the solar panel, creating an XYZ solid around it and defining your fluid domain with the solar panal as a cut out solid. I'm not sure where you are at with this though.

1) Boundary conditions. I guess on one side of your domain you would need some sort of free stream 90 mph inlet section. You can add a profile with the expression language if you want. On the opposite end of the domain probably a static pressure outlet will be just fine.

2) Yes it is possible to use CFX-5.5 to do this. Create the geometry, define the problem physics (just air I assume) and boundary conditions, then do grid, run the solver and post process. You can get the forces on the solar panels directly out of CFX-Post, just remember to turn on "Output Equation Flows" in the solver control panel in CFX-Build.

3) I'm not exactly sure what you mean by this question. Once you setup and run the problem you can get the forces directly from CFX-Post.

You sound like maybe your a beginner with CFX-5.5? I'm not sure though. I suggest you do the Wing or Pipe Valve tutorial to get the idea of how CFX-5 works. You should also be able to calculate the forces on the valve and wing, which will show you how to do this for your solar panel project. The approach is the same.


jabe April 20, 2002 18:28

Re: interfced coupled system
Hi neale, thank for your help I followed your instructions in how to create the geometry. I got it right this time. my new problem is finding the forces on the panel. I have got the results at the cfx-post but I still can not find a way to find the forces acting on the panel. please tell me what do u think I should do to find the forces acting on my(4 2 .2) panel by 90 miles/hr wind? By the way you are right I am a beginner, thanx and bye

Mike April 22, 2002 19:28

Re: interfced coupled system
The forces on the boundaries are printed at the end of the .out (which you can find in the same directory as the res file). You will have two sets of data - the pressure forces and the viscous forces in the X, Y and Z directions. The sum of the pressure and viscous forces will be the total force in that direction. You can also use the Function Calculator in CFX-Post. An areaInt of Pressure will give the same value as the Pressure force printed in the out file.

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