Marine turbine

kseon · October 19, 2012, 08:59

Hi all

I am trying to do marine turbine simulation.
it should be placed 1 meter under the sea level, therefore the water pressure should be around 1 bar.
should i use operation condition to set 1 bar of water pressure or is there another way to set-up this condition?

thanks in advance.

Jeremie84 · October 19, 2012, 15:46

Hi,

One option could be setting the operating pressure at 0, and the pressure outlet at the pressure corresponding to the depth of the turbine location (in your case, it is 1m, so you could set the pressure outlet at a little bit more than 1 bar).

Jeremie

kseon · October 22, 2012, 10:39

Thanks for your reply Jeremi84.
so it is much better leave operation condition as dafault and change outlet gauge pressure as 101325 pascal, is that correct?
then how about the inlet gauge pressure?
do i need to change as well as 101325?

Kseon

kseon · October 22, 2012, 11:10

Quote:

Originally Posted by Jeremie84

Hi,

One option could be setting the operating pressure at 0, and the pressure outlet at the pressure corresponding to the depth of the turbine location (in your case, it is 1m, so you could set the pressure outlet at a little bit more than 1 bar).

Jeremie

Hi Jeremie

Thanks for your reply Jeremi84.
so it is much better leave operation condition as dafault and change outlet gauge pressure as 101325 pascal, is that correct?
then how about the inlet gauge pressure?
do i need to change as well as 101325?

Kseon

Jeremie84 · October 22, 2012, 11:32

Hello kseon,

"absolute pressure = operating pressure + gauge pressure"
The pressures you set for your pressure-inlet and pressure-outlet are "gauge pressure". So you have 2 options:
- you may set the operating pressure at 0. In that case, you will set your pressure-outlet at 101 325 Pa.
- or you may set the operating pressure at 101 325 Pa (default). Here, you will set your pressure-outlet at 0.

I guess you are simulating an incompressible flow. So, these 2 options will give identical results (operating pressure could be significant for low-Mach-number compressible flows).

For the inlet BC, I would suggest a velocity-inlet since you have an incompressible flow. But, pressure-inlet is good too. To determine the pressure-inlet, you have to deduce the pressure from the upstream flow velocity, using the Bernoulli's principle.

Regards,

Jeremie

kseon · October 26, 2012, 07:38

Thanks Jeremie!!!!

it helped me a lot!!!!

regards

Kseon

October 19, 2012, 08:59	Marine turbine	#1
kseon New Member Join Date: Nov 2011 Posts: 4 Rep Power: 14	Hi all I am trying to do marine turbine simulation. it should be placed 1 meter under the sea level, therefore the water pressure should be around 1 bar. should i use operation condition to set 1 bar of water pressure or is there another way to set-up this condition? thanks in advance.

October 22, 2012, 10:39		#3
kseon New Member Join Date: Nov 2011 Posts: 4 Rep Power: 14	Thanks for your reply Jeremi84. so it is much better leave operation condition as dafault and change outlet gauge pressure as 101325 pascal, is that correct? then how about the inlet gauge pressure? do i need to change as well as 101325? Kseon Last edited by kseon; October 22, 2012 at 11:18. Reason: want to delete

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October 19, 2012, 15:46		#2
Jeremie84 Member Join Date: Mar 2011 Location: Canada Posts: 35 Rep Power: 15	Hi, One option could be setting the operating pressure at 0, and the pressure outlet at the pressure corresponding to the depth of the turbine location (in your case, it is 1m, so you could set the pressure outlet at a little bit more than 1 bar). Jeremie

October 22, 2012, 11:32		#5
Jeremie84 Member Join Date: Mar 2011 Location: Canada Posts: 35 Rep Power: 15	Hello kseon, "absolute pressure = operating pressure + gauge pressure" The pressures you set for your pressure-inlet and pressure-outlet are "gauge pressure". So you have 2 options: - you may set the operating pressure at 0. In that case, you will set your pressure-outlet at 101 325 Pa. - or you may set the operating pressure at 101 325 Pa (default). Here, you will set your pressure-outlet at 0. I guess you are simulating an incompressible flow. So, these 2 options will give identical results (operating pressure could be significant for low-Mach-number compressible flows). For the inlet BC, I would suggest a velocity-inlet since you have an incompressible flow. But, pressure-inlet is good too. To determine the pressure-inlet, you have to deduce the pressure from the upstream flow velocity, using the Bernoulli's principle. Regards, Jeremie

October 26, 2012, 07:38		#6
kseon New Member Join Date: Nov 2011 Posts: 4 Rep Power: 14	Thanks Jeremie!!!! it helped me a lot!!!! regards Kseon