Benchamark study of CAARC building

p_kmb · August 18, 2015, 08:18

Hi all,
I'm trying to recreate cfd study described in this paper of Huang and Li http://www.sciencedirect.com/science...43974X06001593

I've couple problems.

As it is shown in the article there should be some oscillations of Cd and CL for LK and MMK RANS model, which I cannot obtain (maybe mesh problem). I tried LES, and got nice oscillations and vortex shedding.

So starting from my last struggle:
For LES there is pretty good agreement of the Cd and Cl, but the pressure coefficient on the front wall is around 0.3. In the reference tab for pressure value I used 0. Should it be something else?

The boundary conditions:
velocity inlet
outflow
wall slip condition for roof and side walls walls of the domain

for RANS:
k-e standard or Kato Launder
enhanced wall function

It is said to use PISO for transient simulations but I got an error: floating point exception. The values of Cd and CL for RANS simulations are ok. The problem is that they don't oscillate, the flow is steady although it shouldn't be with the sharp corners and Re=1e5.

I count on your help.
Paulina

p_kmb · August 24, 2015, 10:41

I red some other threads about pressure and pressure coefficient.

In my incompressible flow case, I've velocity inlet and outflow.
The operating condition and reference pressure location are fluent default 1 atm and (0,0,0).
The (0,0,0) point is in the middle of my model. Moving the ref point location to the inlet plane (-1.1585,0,0) changes max Cp value at the front wall of the building to 0.89. And I leave the pressure in the reference value tab equal to 0.

Am I right to change the location? If yes, what is the right location for reference pressure? Should I change also the z coordinate?

August 18, 2015, 08:18	Benchamark study of CAARC building	#1
p_kmb New Member Paulina Join Date: Oct 2012 Posts: 23 Rep Power: 13	Hi all, I'm trying to recreate cfd study described in this paper of Huang and Li http://www.sciencedirect.com/science...43974X06001593 I've couple problems. As it is shown in the article there should be some oscillations of Cd and CL for LK and MMK RANS model, which I cannot obtain (maybe mesh problem). I tried LES, and got nice oscillations and vortex shedding. So starting from my last struggle: For LES there is pretty good agreement of the Cd and Cl, but the pressure coefficient on the front wall is around 0.3. In the reference tab for pressure value I used 0. Should it be something else? The boundary conditions: velocity inlet outflow wall slip condition for roof and side walls walls of the domain for RANS: k-e standard or Kato Launder enhanced wall function It is said to use PISO for transient simulations but I got an error: floating point exception. The values of Cd and CL for RANS simulations are ok. The problem is that they don't oscillate, the flow is steady although it shouldn't be with the sharp corners and Re=1e5. I count on your help. Paulina

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August 24, 2015, 10:41		#2
p_kmb New Member Paulina Join Date: Oct 2012 Posts: 23 Rep Power: 13	I red some other threads about pressure and pressure coefficient. In my incompressible flow case, I've velocity inlet and outflow. The operating condition and reference pressure location are fluent default 1 atm and (0,0,0). The (0,0,0) point is in the middle of my model. Moving the ref point location to the inlet plane (-1.1585,0,0) changes max Cp value at the front wall of the building to 0.89. And I leave the pressure in the reference value tab equal to 0. Am I right to change the location? If yes, what is the right location for reference pressure? Should I change also the z coordinate?