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variable pressure at inlet boundary

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Old   August 22, 2008, 06:16
Default variable pressure at inlet boundary
  #1
Stephanie
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the inlet temperature varies over the time. the mass flow is constant.

the inlet pressure should also vary since the temperature is varying. How to do that in Star v3 or v4?
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Old   August 22, 2008, 07:48
Default Re: variable pressure at inlet boundary
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Richard
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You do not specify the inlet pressure: the temperature and the massflow are enough to determine the solution (at least for subsonic flow). The pressure at the inlet is then part of the solution. If you were to specify the inlet pressure too, you would over-constrain the system.
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Old   August 22, 2008, 12:49
Default Re: variable pressure at inlet boundary
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James
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If you know the pressure at a point on the inlet boundary and are using an outlet boundary then you can specify one of the cells next to the boundary as the pressure reference cell.

Perhaps this will satisfy part of your goal.
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Old   August 23, 2008, 06:04
Default Re: variable pressure at inlet boundary
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Reza
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Hi,

use a user subroutine BCDEFI.f for a variable inlet boundary. In the Navigator, specify the inlet boundary to use the sub routine you have written.

since Massflow=rho*velocity*area, you should be able to find all those declared variables in nom.inc.

examples are in: Utilities--> User subroutine.

start the simulation along with the ufile directory. Then you set to go.

more on the use of ufile...please refer to the user manual.

Reza

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