[heydari]

Hi;
If we want to use two-dimensional solution,
1. Which thickness can be used to model (for example, thickness of model is 7.5 cm,in two-dimensional model, how much?)
2. What proportion of the input should be a discharge plan (for example, 1.5 liters per second flow rate of input, how much in two-dimensional model?)

[Steffen595]

trawl through the recent posts. There was something that Ansys assumes the depth with 1m

[ghorrocks]

Q1: See FAQ: http://www.cfd-online.com/Wiki/Ansys..._simulation.3F
Q2: A 2D planar model will have a flow rate like 10 l/s per metre. In CFX as you are modelling the depth you have to scale it accordingly - so if your mesh is 0.1m thick then you would need to apply 1 l/s.

[falsc233]

Originally Posted by ghorrocks

Q1: See FAQ: http://www.cfd-online.com/Wiki/Ansys..._simulation.3F
Q2: A 2D planar model will have a flow rate like 10 l/s per metre. In CFX as you are modelling the depth you have to scale it accordingly - so if your mesh is 0.1m thick then you would need to apply 1 l/s.

sorry for replying to this ages-old thread, but is there any reason why the 2D planar mesh extrusion thickness should be about the same as the element edge length? I understand this is the recommendation from the solver modeling guide, but since the front and back surfaces are both symmetry, would the thickness matter at all? I'm asking because when I change the extrusion thickness in a 1D conduction model, the exiting heat flux do show a small variation which I was not expecting.

[Opaque]

If you are running double precision, and reasonable aspect ratio for the mesh it should not matter.

However, if the planes are too far apart, high aspect ratio and single precision, you must recall that Ansys CFX is vertex based; therefore, there are two solution fields on each symmetry plane and because a solution algorithm is not perfectly symmetric, you may get into spurious iterations and it may take longer to converge.