prescribe pressure on inner face

Yannian · January 10, 2012, 14:32

hi,everybody
As the fan model build by ANSYS, I want to prescribe the pressure by myself not using fan model. Because the magitude of pressure is equal on both sides of the disk but I this is not what I want.
I decide to built one face as the disk, and use udf to prescribe pressure jump to make it different on the two sides of the disk. can you tell me how I can achieve it?
Best regards!
Yannian

takin · January 10, 2012, 23:55

Dear Yannian!
really, I did not understand what exactly you want to do. generally, setting the level of pressure at inlet boundries has some limitations. the value of pressure at inlet boundaries are aften resulted from the outlet pressure value.
In fan model, FLUENT asumes a pressure difference between two sides of the surface that yields to a driving force for flow. but if you set the value of pressure manually, no driving force would be generated.
If you get some additional information, I would be able to help you more.

Yannian · January 11, 2012, 03:41

Dear takin,
The model is a propeller. I want to use disk to simulate it. The fan model used in FLUENT adopt classic actuator disk model. When I checked the pressure jump in this model I found that the pressure was prescribed the same maginute and the opposite sign, such as -5 and 5, so the pressure jump is 10. The propeller I use is not like this situation, the magnitude of pressure must be different, such as -8 and 2, the pressure jump is 10 also.

January 10, 2012, 14:32	prescribe pressure on inner face	#1
Yannian Member Yolk Join Date: Nov 2011 Posts: 38 Rep Power: 14	hi,everybody As the fan model build by ANSYS, I want to prescribe the pressure by myself not using fan model. Because the magitude of pressure is equal on both sides of the disk but I this is not what I want. I decide to built one face as the disk, and use udf to prescribe pressure jump to make it different on the two sides of the disk. can you tell me how I can achieve it? Best regards! Yannian

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January 10, 2012, 23:55		#2
takin New Member MK Join Date: Aug 2009 Posts: 22 Rep Power: 16	Dear Yannian! really, I did not understand what exactly you want to do. generally, setting the level of pressure at inlet boundries has some limitations. the value of pressure at inlet boundaries are aften resulted from the outlet pressure value. In fan model, FLUENT asumes a pressure difference between two sides of the surface that yields to a driving force for flow. but if you set the value of pressure manually, no driving force would be generated. If you get some additional information, I would be able to help you more.

January 11, 2012, 03:41		#3
Yannian Member Yolk Join Date: Nov 2011 Posts: 38 Rep Power: 14	Dear takin, The model is a propeller. I want to use disk to simulate it. The fan model used in FLUENT adopt classic actuator disk model. When I checked the pressure jump in this model I found that the pressure was prescribed the same maginute and the opposite sign, such as -5 and 5, so the pressure jump is 10. The propeller I use is not like this situation, the magnitude of pressure must be different, such as -8 and 2, the pressure jump is 10 also.