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swe704 April 8, 2009 09:57

Impinging jet
 
Dear all,

I am a new user of Fluent and now simulating impinging jet ventilation in a room.Air is supplied though a elliptical pipe,the distance from the outlet to the floor is 0.6meter.Due to some reasons, some simplifications have been added in this case: 1. the only objet inside room is supply pipe,nothing else;2 exhaust has been extended 1meter long outside the room.3 simulate isothermal case,which means energy equation is not involved.

Inlet boundary condition is mass flow rate though it's incompressible, air flow rate is known but the equivalent diameter is hard to get in this case.outlet is outflow.

All the meshes are structure by spliting the room into several parts,and fine mesh is applied on the region of impingement on the floor, the wall installed the elliptical supplying pipe, as well as all the parts close to walls.

First simulation,choose standard k-e with standard wall function, but get somewhat higer wall y plus on the other walls(all the other walls without installed pipe, the velocity around those walls are quite low).After refine all the mesh in Gambit, still get higer wall y plus(rang form 1-44)

Please give me some advices about the following concerns:
1. which parameters are better to be checked to judge the reslults getting to know if it is correct or wrong, and how can i find the error source.
2. How can i control y plus for the whole room,should i use Boundary layer in Gambit? If knowing y plus,check wall shear stress then know friction velocity,get y.Or do you have any other way to get y.

3. For 3D case, which way is better for showing when ploting xy,eg,if i choose a surface, it will show all the values for the surface and it's hard to see clearly and find value on exact point. If i want to see the values on the centerline of one surface,how can i do.

4.I don't have any data that can be compared, later those results will be uesd for conducting my experiment.so i need to get close to correct simulation.

5.Any suggestions about impinging jet,(turbulent model, wall treatment....)


I am looking forward to your reply,thanks in advance.


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