Date of Award


Degree Name

Doctor of Philosophy


Mechanical and Aerospace Engineering

First Advisor

Dr. Bade Shrestha, Ph.D.

Second Advisor

Dr. Koorosh Naghshineh, Ph.D.

Third Advisor

Dr. Tianshu Liu, Ph.D.

Fourth Advisor

Dr. Viktor Kilchyk, Ph.D.


Aerodynamic noise, aerodynamic performance, renewable energy, wind energy, wind turbines


This work numerically and experimentally investigates the effect of using channels inside airfoils on the noise level as a possible resolution for aerodynamic noise generated by wind turbines. The work also investigates aerodynamic performance and turbulence around the employed airfoils. The results reveal that some of the samples show some improvement in reducing the aerodynamic noise. The reduction of the aerodynamic noise is explained as the trailing edge blowing injection that reduces the wake momentum deficit of the blade and reduces the pressure fluctuation which is responsible for noise production. Particularly, the angles of channel inclination with respect to the cord was the dominant factor that reduces the aerodynamic noise generated by wind turbines. Previous studies of supersonic channels show an increase in lift and decrease in drag. In this study, different sizes and directions of channels were created inside the NACA 0012 airfoil and have been tested under subsonic flow. The effect of these channels was investigated on both drag (D) and lift (L) coefficients experimentally and numerically. The channels were made at three different diameter sizes of 0.05, 0.08, and 0.1 inches and with four inclination angles of -1, 0, 2, and 3 degrees with respect to the chord. The results show an increase in drag coefficients and decrease in lift coefficients for all the channeled samples compared to the regular unchanneled airfoil, hence decreasing the ratio (L/D). In this study, with subsonic flow, the skin friction drag (viscous drag) is dominant, therefore the drag increases with the channels because it increased the skin friction area (wetted area) compared to the airfoil without channels. This work is significant, especially for those people who live close to wind turbine farms, as this work deals with aerodynamic noise around the wind farms.

Access Setting

Dissertation-Open Access