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 nick July 9, 2009 08:05

Ahmed Body Simulation

Dear All,
I am pretty fresh on CFD simulation. Currently I am doing a simulation on Ahmed Model with 25deg slant angel in Fluent. I am looking for the Drag Coefficient. According to the experiment results (SR Ahmed 1984), the pressure drag coefficient at the front part is around 0.02, the back part is around 0.08 and the slant surface is around 0.15.

The Simulation was under following Setting:

Hex Mesh with around 4 million cells
Domain is 9.2(x) x 1.87(y) x 1.4(z)
LES Viscous model
BC:
40m/s inlet velocity
Symmetry the sides and top of the domain

“References Values”
Area: 0.112m^2
Length: 0.288m
Velocity: 40m/s
Viscosity: 1.79 x 10^-5

I tried to record the “Cd” on x-direction for all surfaces from the Fluent function: Solve, Monitors, Force. However, the results of are really bad. The “Cd” of the front part = 0.3, back part = 0.1 and slant part = 0.05 :confused::eek::eek::eek:

I want to know how to get the results of pressure drag coefficient from Fluent?

The equation of the Drag Coefficient is Cd = (drag force)/(0.5 * density * A * V^2)

Thanks a lot on help!:)
Nick

 Saima March 26, 2010 17:37

Hi,

I am working on Ahmed Body, IS there anybody has material about it?

Saima

 Saima March 26, 2010 17:37

Quote:
 Originally Posted by nick (Post 222054) Dear All, I am pretty fresh on CFD simulation. Currently I am doing a simulation on Ahmed Model with 25deg slant angel in Fluent. I am looking for the Drag Coefficient. According to the experiment results (SR Ahmed 1984), the pressure drag coefficient at the front part is around 0.02, the back part is around 0.08 and the slant surface is around 0.15. The Simulation was under following Setting: Hex Mesh with around 4 million cells Domain is 9.2(x) x 1.87(y) x 1.4(z) LES Viscous model BC: 40m/s inlet velocity Symmetry the sides and top of the domain “References Values” Area: 0.112m^2 Length: 0.288m Velocity: 40m/s Viscosity: 1.79 x 10^-5 I tried to record the “Cd” on x-direction for all surfaces from the Fluent function: Solve, Monitors, Force. However, the results of are really bad. The “Cd” of the front part = 0.3, back part = 0.1 and slant part = 0.05 :confused::eek::eek::eek: I want to know how to get the results of pressure drag coefficient from Fluent? The equation of the Drag Coefficient is Cd = (drag force)/(0.5 * density * A * V^2) Thanks a lot on help!:) Nick
Is there anybody has material about it.

 sega March 26, 2010 18:23

Use GAMBIT!

 Saima May 10, 2010 10:40

I have completed AHmed Body 3D meshing I cant upload here because size is moore then 100KB, if somebody needs send me an email ill send it.

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