[Ranjan]

Hello

I am trying to simulate inviscid flow-field around the NASA CRM wing. Even though my dimensions are correct, I get extremely high values for CL and CD ( almost double ) when compared to the design conditions of AOA ~ 2.34 degrees.

I have tried both manual and automatic values for A_ref ( by setting A_ref zero), the manual entry for A_ref being 191.82 m^2.

I have also tried multiple mesh resolutions, varying from 3-9 Million.


Any suggestions ?

Thanks in advance

[hpatel]

Originally Posted by Ranjan

Hello

I am trying to simulate inviscid flow-field around the NASA CRM wing. Even though my dimensions are correct, I get extremely high values for CL and CD ( almost double ) when compared to the design conditions of AOA ~ 2.34 degrees.

I have tried both manual and automatic values for A_ref ( by setting A_ref zero), the manual entry for A_ref being 191.82 m^2.

I have also tried multiple mesh resolutions, varying from 3-9 Million.


Any suggestions ?

Thanks in advance

What is the x-y-z orientation of your mesh? In relation to that, why is the AOA=0 in the config file?

[Ranjan]

I am not sure what you mean by " why is the AOA in the config file ? "

The flow angle of attack is always defined in the config file. The config file is attached as a .txt file with my post.

Thank you

[punyaplaban]

What is the axis of lift in your mesh? Is it z-axis?

[Ranjan]

I figured out the problem. The axis orientation and the configuration in general were correct. However, Euler flow assumption especially for the CRM wing at design condition leads to spurious ( over-predicted ) aerodynamic characteristics. While one might expect to predict the pressure forces and hence the lift distribution to a reasonable accuracy, the CRM geometry encapsulated viscous effects such as shock-induced boundary layer separation , a phenomenon absent in Euler assumption.

Upon switching to RANS and a computational domain with appropriate near-wall resolution ( yPlus ~ 1 ), the flow characteristics computed were reasonable when compared to other numerical experiments.

Thank you all !