Pressure coefficient plot for rotating problems

eddick · January 10, 2020, 08:58

Hi there!

I have a quite trivial question guys - if I have a simple rotating flow with pressure-inlet and pressure-outlet BCs, where the flow is only driven by the rotation of the impeller, how can I plot the Pressure coefficient value?
As the denominator says(1/2*ro*Uinf^2) I need the value of the infinity's velocity but hey, there is no such velocity because I don't have velocity-inlet, so what value should I put as Uinf ?

Thanks a lot
Adrian

agd · January 10, 2020, 11:00

Typically a velocity is constructed from the rotational speed and a characteristic length - for example, use W*R, where W is the angular velocity of the driver, and R is the radius (assuming this is some type of impeller disk or such thing). If you have access to any literature in the area you are working in, you should be able to find some standard type definitions.

eddick · January 13, 2020, 01:55

Thank you for your advice, that is kind of working for now but I will keep an eye on this topic and look for insights.

January 10, 2020, 08:58	Pressure coefficient plot for rotating problems	#1
eddick New Member Adrian P. Join Date: Jul 2019 Posts: 3 Rep Power: 6	Hi there! I have a quite trivial question guys - if I have a simple rotating flow with pressure-inlet and pressure-outlet BCs, where the flow is only driven by the rotation of the impeller, how can I plot the Pressure coefficient value? As the denominator says(1/2roUinf^2) I need the value of the infinity's velocity but hey, there is no such velocity because I don't have velocity-inlet, so what value should I put as Uinf ? Thanks a lot Adrian

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January 10, 2020, 11:00		#2
agd Senior Member Join Date: Jul 2009 Posts: 351 Rep Power: 18	Typically a velocity is constructed from the rotational speed and a characteristic length - for example, use W*R, where W is the angular velocity of the driver, and R is the radius (assuming this is some type of impeller disk or such thing). If you have access to any literature in the area you are working in, you should be able to find some standard type definitions.

January 13, 2020, 01:55		#3
eddick New Member Adrian P. Join Date: Jul 2019 Posts: 3 Rep Power: 6	Thank you for your advice, that is kind of working for now but I will keep an eye on this topic and look for insights.