|
[Sponsors] |
July 14, 2008, 07:23 |
I am solving for a flow past a
|
#1 |
New Member
Anush
Join Date: Mar 2009
Posts: 5
Rep Power: 17 |
I am solving for a flow past a cylinder in external flow in 2D using the icoFoam solver. It consists of a circle in a rectangular domain.
I'm using the following boundary conditions: 1. Left side of the rectangle is the inlet with fixedValue velocity and zeroGradient pressure. 2. Right side of the rectangle is the outlet with fixedValue pressure and zeroGradient velocity. 3. fixedValue for velocity and zeroGradient pressure at the surface of the cylinder. I have the following doubts: 1. Are the above conditions I've used correct? 2. I don't know what conditions to use for the top and bottom sides of the rectangle. Should I treat them as outlets as well? 3. What would be the difference between specifying the walls of the cylinder as 'wall' or 'patch'? Does the difference come into play only in turbulence simulations? Thanks for the help. |
|
July 14, 2008, 08:06 |
1/correct
2/if inlet velocity
|
#2 |
Member
Patrick Bourdin
Join Date: Mar 2009
Posts: 40
Rep Power: 17 |
1/correct
2/if inlet velocity is parallel to bottom and top planes, you can use the 'slip' BC on these (however make sure bottom and top planes are far enough from the cylinder for this BC to be physically correct for external flow, otherwise you will spuriously accelerate the fluid over the cylinder). 3/It shouldn't make any difference for a laminar solver whether you use wall or patch in the boundary file |
|
July 14, 2008, 08:41 |
Hey thanks a lot, Patrick.
|
#3 |
New Member
Anush
Join Date: Mar 2009
Posts: 5
Rep Power: 17 |
Hey thanks a lot, Patrick.
And also, Would 'slip' be a better condition to use than zeroGradient for both pressure and velocity? If so, why - does it not unnecessarily remove the normal component? |
|
July 14, 2008, 10:13 |
I don't know what is better.
|
#4 |
Member
Patrick Bourdin
Join Date: Mar 2009
Posts: 40
Rep Power: 17 |
I don't know what is better.
The slip BC may stabilize the computation more than the other, try both settings, and see what happens. All in all, if both BCs work fine for your case, you should obtain very similar solutions (for top and bottom planes far enough from the cylinder). |
|
July 14, 2008, 12:18 |
Oh okay. Thank you very much!
|
#5 |
New Member
Anush
Join Date: Mar 2009
Posts: 5
Rep Power: 17 |
Oh okay. Thank you very much!
|
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
External Incompressible flow Boundary conditions | Himanshu Almadi | FLUENT | 2 | November 13, 2009 09:17 |
Fan Boundary conditions with external analysis | Rob | FloEFD, FloWorks & FloTHERM | 1 | February 10, 2009 00:04 |
Boundary conditions for external flows | ryan_m | OpenFOAM Running, Solving & CFD | 3 | May 19, 2008 09:49 |
boundary conditions for external automotive aero | Andrew Berner | FLUENT | 4 | November 2, 2006 11:17 |
Appropriate boundary conditions for external incompressible flow | mattamos | OpenFOAM Running, Solving & CFD | 7 | July 28, 2005 12:03 |