About gravity in Finite Volume Methods Coding

hjxy2012 · May 21, 2017, 22:28

Hello, I am writing a FVM code and it works well without gravity. But after adding gravity terms to the momentum equations the result is wrong. I just want to simulate the pressure difference caused by gravity(hydrostatic pressure). This pressure difference will exist even the fluid is still. I know in Fluent, if I want to take it into consider, I have to set the gravity and set reference density to 0. Then what should I do with my own code? Thank you.

FMDenaro · May 22, 2017, 03:41

Give more details about your discretization, it is likely a numerical instability ..

hjxy2012 · May 22, 2017, 05:14

Than you for your reply.
I get some ideas from this issue:
Hydrostatic Pressure and Gravity
The hydrostatic pressure is not taken into consideration when we are building momentum equations. And I have to add the hydrostatic pressure from this:
p = pd + rho*g*z

May 21, 2017, 22:28	About gravity in Finite Volume Methods Coding	#1
hjxy2012 New Member Green Join Date: Apr 2016 Posts: 27 Rep Power: 10	Hello, I am writing a FVM code and it works well without gravity. But after adding gravity terms to the momentum equations the result is wrong. I just want to simulate the pressure difference caused by gravity(hydrostatic pressure). This pressure difference will exist even the fluid is still. I know in Fluent, if I want to take it into consider, I have to set the gravity and set reference density to 0. Then what should I do with my own code? Thank you. Last edited by hjxy2012; May 22, 2017 at 00:02.

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May 22, 2017, 03:41		#2
FMDenaro Senior Member Filippo Maria Denaro Join Date: Jul 2010 Posts: 6,896 Rep Power: 73	Give more details about your discretization, it is likely a numerical instability ..

May 22, 2017, 05:14		#3
hjxy2012 New Member Green Join Date: Apr 2016 Posts: 27 Rep Power: 10	Than you for your reply. I get some ideas from this issue: Hydrostatic Pressure and Gravity The hydrostatic pressure is not taken into consideration when we are building momentum equations. And I have to add the hydrostatic pressure from this: p = pd + rhogz