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Old   October 28, 2007, 10:20
Default Hypersonic problem
  #1
Subramani Sockalingam
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What I am trying to do is to find the solution where pressure, temperature and Mach number are 8.1757 Pa, 227 K and 22.41 (freestream conditions). I started with Mach 2 and increased the Mach number using the same pressure and temperature. At Mach 8 the absolute pressure was limited to the minimum 1 in a number of cells and the Mach number at some point in the domain became 90. Why would this happen? I am running a 2D inviscid implicit density based model.

Thanks, Subramani
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Old   October 30, 2007, 09:02
Default Re: Hypersonic problem
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Glenn
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Are your 8.1757 Pa and 227 K values total or static conditions? I suspect they may be static conditions. In a Mach 22.41 operation, your total pressure and temperature would be much, much higher. In that case, you should raise the total pressure and temperature in relationshop to the Mach number and set that as your inflow boundary condition (Total Pressure Inlet). Conversely, if 8.1757 Pa is total pressure at Mach 22.41, your corresponding static pressure would be well below 1. Pa. Respecify the lower bounds limit for pressure and temperature in your analysis so Fluent is allowed to go to these low presures. Hope this helps.
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Old   October 30, 2007, 10:11
Default Re: Hypersonic problem
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Subramani Sockalingam
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Thanks. They are static conditions. I have raised the upper limits for pressure and temperature. I am facing difficulty in the lower limit.

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Old   November 27, 2007, 17:16
Default Re: Hypersonic problem
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raj
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re calculate ur values with inclusion of Mach no..and try to use density based solver instead of pressure based for good shock prediction and convergence...try ur analysis with saplart-almars turbulence in first attempt...gud luck...
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Old   December 12, 2007, 08:57
Default How to give an pressure inlet in Fluent
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Vijayaragavan
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Dear Friends,

I am doing my project in Fluent,in Fluent software in pressure inlet boundary condition panel there is two column 1. Total gauge pressure 2. Intial\Sonic pressure.

My model is just a U tube pipe in that i want to know the pressure drop of a fluid, say my inlet condition is 2 bar. So in which column i have to give my pressure inlet, and how much i have to give pressure value. And i tried this many times but my result of static pressure drop is showing from 10e-12 to 5e5, and i dont know how to do it...........Please help me friends............

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