same Drag Coefficient

Amir

Hi,

I'm modeling a turbine ventilator Which looks like a backward centrifugal fan. In this case I run simulation for 5 different speeds from 7 to 25 meter per second which correspond to Reynolds numbers of approximately 6.8*e04 to 1.9*e05 and rotation speeds of 230 to 850 rpm.

For all the mentioned cases I got the approximately same drag coefficient of 0.44. also lift coefficient are also same. It doesn't match to experiments which shows the drag coefficients decrease by increasing the free stream velocity.

I double checked the reference values.

I wonder if its about the induced drag!! or something else.

Any comment is well appreciated.

Regards, Amir.