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Fluent Drag Estimations are Twice Experimental Data

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Old   June 19, 2017, 16:56
Default Fluent Drag Estimations are Twice Experimental Data
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Thusitha
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Hi,

I'm having difficulty in matching experimental aerodynamic data (drag) for naca0006.

The fluent simulations results seems to be roughly twice the experimental data for up to 10deg.

The speed, RE, Mach, Density, Pressure, Viscosity are: 42.023 m/s, 0.124, 1.225 kg/m3, 101325 pa, 1.716e-5 kg/sm.

Turbulence intensity, length scale, modified turbulent viscosity are: 0.00069%, 0.0078, 2.77e-6.

Pressure based model/spalart allmaras viscous model. The y+ is below 1 and the plate length is 1m.


Can anyone point out what's wrong?


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Old   June 19, 2017, 22:53
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the drag coefficient is computed using the reference values. Make sure those are correct. I think you can set the compute from "inlet"
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Old   June 20, 2017, 03:10
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Quote:
Originally Posted by diamondx View Post
the drag coefficient is computed using the reference values. Make sure those are correct. I think you can set the compute from "inlet"


Hi,

Thank you for your reply.

Does it apply for Lift as well? Because, Lift is a good match; it's the drag that doesn't disagree.

I tried various values for boundary conditions (turbulent intensity, length scale, modified turbulent viscosity etc.), but the result is the same.

I have also tried with two grids: one coarse and one fine, still the result is the same.

BR
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Old   June 20, 2017, 03:16
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Quote:
Originally Posted by diamondx View Post
the drag coefficient is computed using the reference values. Make sure those are correct. I think you can set the compute from "inlet"


PS - The reference values are computed from Inlet as well (see my previous comment)


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