Atmospheric Bounduary Layer - Problens with hidrostact pressure

camilo_costa · August 18, 2009, 18:38

Dear friends!

I am trying to simulate a ABL problem, but i still have problems with my Outlet boundary . When i set on for bouncy, the solver automatically adds a contribution for hydrostatic pressure in my model and resolve the solution with this hidrostatic pressure. Actually i put a prescribed velocity in my outlet condition, but i need change this condition for a average static pressure for the solver resolve correct the velocity field. The question is, the solver will put a automatic hydrostatic pressure contribution in my outlet condition or i need put a function that describe this hydrostatic pressure, by a specific CFX EXPRESSION LANGUAGE, for ABL flow`s?

If i need put this CEL, what the correct function that describe this hydrostatic pressure for may outlet condition. Remember that, the reference pressure in my domain is 0 Pa and the fluid that i am using is a real gas fluid, with density variable with temperature and pressure.

THX FOR ALL!!!

camilo_costa · August 19, 2009, 00:17

Thx for all, but i am already find the solution.

Is very simply, just put a opening boundary condition, and set with opening pressure condition instead static pressure condition and put atmospheric pressure that you put in the top of your domain!!! The solver will add automatically a hydrostatic contribution in outlet boundary condition.

Thx!!

mechovator · August 19, 2009, 01:34

What is ABL?
Are you modeling some kind of open channel flow?

ghorrocks · August 19, 2009, 07:58

ABL = atmospheric boundary layer

mechovator · August 24, 2009, 23:33

thank you garrlock

camilo_costa · August 25, 2009, 10:56

I change the opening pressure for static pressure and the results are the same! Just a coment!

August 18, 2009, 18:38	Atmospheric Bounduary Layer - Problens with hidrostact pressure	#1
camilo_costa Member Camilo Costa Join Date: Jun 2009 Posts: 34 Rep Power: 16	Dear friends! I am trying to simulate a ABL problem, but i still have problems with my Outlet boundary . When i set on for bouncy, the solver automatically adds a contribution for hydrostatic pressure in my model and resolve the solution with this hidrostatic pressure. Actually i put a prescribed velocity in my outlet condition, but i need change this condition for a average static pressure for the solver resolve correct the velocity field. The question is, the solver will put a automatic hydrostatic pressure contribution in my outlet condition or i need put a function that describe this hydrostatic pressure, by a specific CFX EXPRESSION LANGUAGE, for ABL flow`s? If i need put this CEL, what the correct function that describe this hydrostatic pressure for may outlet condition. Remember that, the reference pressure in my domain is 0 Pa and the fluid that i am using is a real gas fluid, with density variable with temperature and pressure. THX FOR ALL!!!

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August 19, 2009, 00:17		#2
camilo_costa Member Camilo Costa Join Date: Jun 2009 Posts: 34 Rep Power: 16	Thx for all, but i am already find the solution. Is very simply, just put a opening boundary condition, and set with opening pressure condition instead static pressure condition and put atmospheric pressure that you put in the top of your domain!!! The solver will add automatically a hydrostatic contribution in outlet boundary condition. Thx!!

August 19, 2009, 01:34		#3
mechovator Member mechovator Join Date: May 2009 Posts: 32 Rep Power: 16	What is ABL? Are you modeling some kind of open channel flow?

August 19, 2009, 07:58		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,700 Rep Power: 143	ABL = atmospheric boundary layer

August 24, 2009, 23:33		#5
mechovator Member mechovator Join Date: May 2009 Posts: 32 Rep Power: 16	thank you garrlock

August 25, 2009, 10:56		#6
camilo_costa Member Camilo Costa Join Date: Jun 2009 Posts: 34 Rep Power: 16	I change the opening pressure for static pressure and the results are the same! Just a coment!