why the absolute pressure is below zero

Steven_Wu_MAX · April 25, 2021, 00:16

I use fluent to simulate a 2D deep cavity, the model is laminar. Boundary condition: velocity inlet and outflow, I use outflow because I do not know the back pressure and I hope the flow can flow through the outlet naturally. the gas is an incompressible ideal gas because the outflow does not allow the compressible gas. the operation pressure is 101325Pa. the gauge pressure I input is 0. but why the result shows that the absolute pressure is below zero?

LuckyTran · April 25, 2021, 00:30

That's a good question because the default limiter won't let the absolute pressure go below 1 Pa. Maybe you can gather your facts and present them better and then maybe someone can help.

fluid-user · April 19, 2022, 09:54

I meet the same question.

April 25, 2021, 00:16	why the absolute pressure is below zero	#1
Steven_Wu_MAX New Member Shanghai Join Date: Nov 2020 Posts: 3 Rep Power: 5	I use fluent to simulate a 2D deep cavity, the model is laminar. Boundary condition: velocity inlet and outflow, I use outflow because I do not know the back pressure and I hope the flow can flow through the outlet naturally. the gas is an incompressible ideal gas because the outflow does not allow the compressible gas. the operation pressure is 101325Pa. the gauge pressure I input is 0. but why the result shows that the absolute pressure is below zero?

April 19, 2022, 09:54	The same question	#3
fluid-user New Member wgp Join Date: Feb 2022 Posts: 3 Rep Power: 4	I meet the same question. Last edited by fluid-user; April 19, 2022 at 10:57.

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April 25, 2021, 00:30		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,683 Rep Power: 66	That's a good question because the default limiter won't let the absolute pressure go below 1 Pa. Maybe you can gather your facts and present them better and then maybe someone can help.