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Pressure profile in Velocity inlet

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Old   June 13, 2020, 12:04
Default Pressure profile in Velocity inlet
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Hi everyone,
I performed a DES simulation of a pipe flow discharging in an open domain like in figure.
During the simulation, at the yellow interface; velocity, pressure, temperature, and turbulence profiles have been captured every 5 timestep using the command "write profile".

Now I want to set the recorded profiles as unsteady inlet BC of a new (more complex) simulation.
The BC type that I have chosen for the new simulation is "velocity inlet" so that i can set velocity components, temperature, Pressure and turbulence from recorded profiles.

The problem is that actually I can't impose the static pressure at the velocity-inlet BC so the calculated static pressure is different from the recorded one and so the density and so the total mass flow rate. Any ideas on how I can set the pressure profile in a velocity inlet BC? [I have read the user guide and it seems impossible]

(with mass flow inlet BC I'll have the problem of a wrong velocity profile)
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Old   June 15, 2020, 07:24
Default Velocity and Pressure
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If you are using velocity inlet, it implies that the simulation is incompressible. And for an incompressible scenario, pressure is not important. It is only the pressure drop that is important. So, you should go ahead and apply velocity and turbulence field and forget about the pressure.
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Old   June 15, 2020, 07:42
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Quote:
Originally Posted by Pertica View Post
The problem is that actually I can't impose the static pressure at the velocity-inlet BC so the calculated static pressure is different from the recorded one and so the density and so the total mass flow rate. Any ideas on how I can set the pressure profile in a velocity inlet BC? [I have read the user guide and it seems impossible]

It's non-physical to specify both velocity and static pressure unless the flow is supersonic. Either way, you need the total pressure. It's too late now but you need to go back and record the total pressure (and total temperature) from your previous case.
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Old   June 15, 2020, 08:30
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Originally Posted by LuckyTran View Post
It's non-physical to specify both velocity and static pressure unless the flow is supersonic. Either way, you need the total pressure. It's too late now but you need to go back and record the total pressure (and total temperature) from your previous case.
I recorded also total pressure. But also in this case if I use pressure inlet (imposing the total pressure) the problem remains
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compressible flows, pressure and velocity, profile, unsteady, velocity inlet

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