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Unable to Capture Shock in Transonic Flow

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Old   January 23, 2009, 02:27
Default Unable to Capture Shock in Transonic Flow
  #1
Tim
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Hi,

I'm modeling transonic flow across a turbine blade.The conditions are blade inlet angle=58.9deg, Mach=0.845, turbulence model is k-w.

I am able to observe Mach numbers of greater than 1 across my blade..However, I am not able to see a shock across the blade?

Any inputs?

Thanks
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Old   January 23, 2009, 15:51
Default Re: Unable to Capture Shock in Transonic Flow
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Koblax
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do you use ideal gas?
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Old   January 23, 2009, 21:05
Default Re: Unable to Capture Shock in Transonic Flow-----
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Yes, I am using Ideal Gas...should i use constant density gas instead??
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Old   January 26, 2009, 08:01
Default Re: Unable to Capture Shock in Transonic Flow
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Tim
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Hi there,

I used constant density gas...It gives me an improved model of the Cp distribution of the blade...However, it is unable to track the shock..

Timothy
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Old   January 26, 2009, 19:58
Default Re: Unable to Capture Shock in Transonic Flow
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anon
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You shouldn't be using constant density for transonic flow. If you say you can see M>1, then somewhere you should also have M<1, that's where your shockwave is. Try making the mesh denser to capture the shock.
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Old   January 28, 2009, 00:37
Default Re: Unable to Capture Shock in Transonic Flow
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Tim
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Hi anon,

Thanks for your reply, tried refining the mesh til the absolute size of the volumetric control is 0.03mm but i still could not detect the shock or drop in Mach in my model.

The chord length is around 60mm fyi...Tried inviscid flow but it still shows the same pressure distribution...Any suggestions ?? Novice in this area.

Tim

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Old   January 29, 2009, 07:05
Default Re: Unable to Capture Shock in Transonic Flow
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Tim
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Hi just to give the full picture...Here are the parameters of my model:

3D, Stationary, Ideal Gas, Coupled FLow, COupled energy, steady,turbulent, RANS, K-E model, turbulence intensity 0.1, turbulence viscosity ratio 500, velocity [272.1,442,0] m/s, temp 987.2K, pressure (gauge) 147675Pa. Using stag inlet for inflow, pressure outlet for outflow, and wall(periodic boundary) for upper and lower part of the model.

Thanks

Tim
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