wind driven flow

EricS · November 8, 2023, 06:58

Hello everyone,

I'm stuck in a problem since a week and I can't figure out how to proceed.

I'm trying to simulate a wind driven flow, I have a domain with two phases, water and air, and I apply a constant velocity in the "air" domain. I want to see how water responds to this.

Since I only have a patch for inlet (for outlet and so on) I'm using multiphaseEulerFoam, rather than interFoam, to avoid splitting the patches. The problem is... my domain is emptying! The water flows out of the domain and I can't keep it inside in any way..

Does anyone have experienced this or have any clue on how the boundary conditions should be set to prevent this problem?

Thank you in advance!

FMDenaro · November 8, 2023, 08:37

Do you need to describe the wave onset or only the flow driven in water?

EricS · November 8, 2023, 08:56

Hi!

I need to describe the onset

FMDenaro · November 8, 2023, 09:00

Quote:

Originally Posted by EricS

Hi!

I need to describe the onset

I think this is a question specific to the use of BCs in OpenFOAM, you should ask in the dedicated sub-section of the forum.

JBeilke · November 8, 2023, 09:03

You need to specity a pressure outlet, where the pressure is a function of the hight of the water p = rho . g . height . This will prevent the water from flowing out.

EricS · November 8, 2023, 09:07

I tried to use prghpressure at the outlet but still the water flows out.. Is there maybe a specific bc for alpha to be set?

JBeilke · November 8, 2023, 09:13

Here is an example from Mr. Peric, how it is done in Comet.

EricS · November 8, 2023, 12:07

Ok I'll try to decode it since I have never used comet ahah
thank you!

JBeilke · November 8, 2023, 13:41

It is likely very similar to the "prghpressure" boundaries :-) I also never used Comet but this user coding is very similar to StarCD.

I never really solved this problem 100%. Usually I ended up splitting the outlet and defining the lower part, which is next to the water as wall. It also worked, when using a normal "Outlet" in StarCCM+.

November 8, 2023, 06:58	wind driven flow	#1
EricS Member Eric Segalerba Join Date: Dec 2021 Location: Italy Posts: 31 Rep Power: 5	Hello everyone, I'm stuck in a problem since a week and I can't figure out how to proceed. I'm trying to simulate a wind driven flow, I have a domain with two phases, water and air, and I apply a constant velocity in the "air" domain. I want to see how water responds to this. Since I only have a patch for inlet (for outlet and so on) I'm using multiphaseEulerFoam, rather than interFoam, to avoid splitting the patches. The problem is... my domain is emptying! The water flows out of the domain and I can't keep it inside in any way.. Does anyone have experienced this or have any clue on how the boundary conditions should be set to prevent this problem? Thank you in advance!

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November 8, 2023, 08:37		#2
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,896 Rep Power: 73	Do you need to describe the wave onset or only the flow driven in water?

November 8, 2023, 08:56		#3
EricS Member Eric Segalerba Join Date: Dec 2021 Location: Italy Posts: 31 Rep Power: 5	Hi! I need to describe the onset

November 8, 2023, 09:03		#5
JBeilke Senior Member Joern Beilke Join Date: Mar 2009 Location: Dresden Posts: 539 Rep Power: 20	You need to specity a pressure outlet, where the pressure is a function of the hight of the water p = rho . g . height . This will prevent the water from flowing out.

November 8, 2023, 09:07		#6
EricS Member Eric Segalerba Join Date: Dec 2021 Location: Italy Posts: 31 Rep Power: 5	I tried to use prghpressure at the outlet but still the water flows out.. Is there maybe a specific bc for alpha to be set?

November 8, 2023, 12:07		#8
EricS Member Eric Segalerba Join Date: Dec 2021 Location: Italy Posts: 31 Rep Power: 5	Ok I'll try to decode it since I have never used comet ahah thank you!

November 8, 2023, 13:41		#9
JBeilke Senior Member Joern Beilke Join Date: Mar 2009 Location: Dresden Posts: 539 Rep Power: 20	It is likely very similar to the "prghpressure" boundaries :-) I also never used Comet but this user coding is very similar to StarCD. I never really solved this problem 100%. Usually I ended up splitting the outlet and defining the lower part, which is next to the water as wall. It also worked, when using a normal "Outlet" in StarCCM+.