Specify velocity components at outlet

jtwilson · August 28, 2015, 05:25

Hey Guys,

I am currently running flow through a geometry with a pressure inlet (non-zero values varying in time) and setting the outlet pressure at zero.

When I sample the total pressure throughout time during the simulation, I get a slightly non-zero pressure value, which is strange because I impose an outlet boundary condition of zero.

Since I know my profile is parabolic at the outlet (and almost Poiseuille-like, resulting in x,y velocity components of zero), I would like to specify these non-axial velocity components (x,y) as zero - I think this may help in convergence and also help rectify the issue with pressure (it's just a thought).

Do any of you know if there is a way to impose this type of boundary condition in Fluent? I am using ANSYS 16.1. Any help would be greatly appreciated.

Thanks!

LuckyTran · August 28, 2015, 11:58

You can impose a velocity profile at the outlet by using a "velocity inlet" as your outlet boundary condition. But you would have to specify the velocity entirely (x,y, & z velocity). I don't think you can specify only two velocity components.

August 28, 2015, 05:25	Specify velocity components at outlet	#1
jtwilson New Member Join Date: Apr 2013 Posts: 6 Rep Power: 13	Hey Guys, I am currently running flow through a geometry with a pressure inlet (non-zero values varying in time) and setting the outlet pressure at zero. When I sample the total pressure throughout time during the simulation, I get a slightly non-zero pressure value, which is strange because I impose an outlet boundary condition of zero. Since I know my profile is parabolic at the outlet (and almost Poiseuille-like, resulting in x,y velocity components of zero), I would like to specify these non-axial velocity components (x,y) as zero - I think this may help in convergence and also help rectify the issue with pressure (it's just a thought). Do any of you know if there is a way to impose this type of boundary condition in Fluent? I am using ANSYS 16.1. Any help would be greatly appreciated. Thanks!

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August 28, 2015, 11:58		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,668 Rep Power: 65	You can impose a velocity profile at the outlet by using a "velocity inlet" as your outlet boundary condition. But you would have to specify the velocity entirely (x,y, & z velocity). I don't think you can specify only two velocity components.