Experimental model of c=0.601m; Where as in the computational model we are using the airfoil of c=1m.
The Re, AOA, velocity, temperature are kept constant for both.
Hello Mr. Paul,
from dimensional analysis, one could conclude that the the pitching moment coefficients of the models (numerical and experimental) have the same value, when the other relevant dimensionless numbers have the same value, i.e Re_M=Re_E and in compressible flow Ma_M=Ma_E. The moment coefficient could be defined by
cm=M(Pitching Torque) / (rho*U_infty^2/2 * Area * chord-length) and thus
cm_M=cm_E
=>
M_E=M_M*/ (rho*U_infty^2/2 * Area * chord-length)_M * (rho*U_infty^2/2 * Area * chord-length)_E
However, you stated that Re and u_infty have the same value at the same time for the model and the experiments. Did you scale the viscosity too?
Best regards
Bastian
Wise option is to re-simulate nearly the experimental geometry conditions. This will take less time than searching the scaling answers
It is a part of developing a methodology for scaling.
The Mach number, AOA and Re was kept constant. So I believe the CL and CD should be same as long as the shape is same as it is a function of Re, AOA and M alone, which are dimensionless.
Where as in case of CM it is dependent of Chord length also ... So i believe we cant directly compare the CM..
Am I right ?
What is the characterisric length in your Reynolds number?
Is the ratio of profile thickness and chord the same?
As stated by Bastian, you don't have to worry about scaling dimensions if the flow conditions are the same. That's why non-dimensional coefficients do exist. Of course, you have to take the same reference point of the experimental model.
Did you find different results between the models?
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