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Velocity overprediction

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Old   June 22, 2003, 06:06
Default Velocity overprediction
  #1
Julie Polyakh
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Hi!

What may cause the flow velocity overprediction of 30% in its maximum point? Problems begin already at the secondary inlet boundary : the U-velocity value after computation is 55% higher than the initial one defined in the BC. The flow swich for BC is 'Fixed Mass'.

Thanks, Julie
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Old   June 22, 2003, 23:57
Default Re: Velocity overprediction
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cjtune
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You should use the 'Fixed Velocity' switch for your second inlet as opposed to 'Fixed Mass'. STAR-CD adjusts the inlet velocity to match the mass flow that you want fixed by (roe)*A*|U|.
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Old   June 24, 2003, 04:54
Default Re: Velocity overprediction
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Julie Polyakh
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Hi,

The problem is that I need mass flow to be fixed... There was no overprediction with more coarse grid even with 'Fixed Mass' option.

Regards,

Julie
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