Experimental and numerical investigations of aerodynamic characteristics for wind turbine airfoil using multi-suction jets

The present work investigates the effects of multi-suction jets on the NACA 0012 airfoil's aerodynamic characteristics at Reynolds number Re equal 0.54 × 105. Experiments and numerical simulations are carried out to this purpose. The surface of the airfoil is equipped with multiple suction slots, and aerodynamic forces are measured as a result. Numerical simulations are employed to illustrate the flow structures on both the modified and unmodified airfoils. The study examines how the lift coefficient, drag coefficient, stall angle, and flow separation are influenced by the location of the airfoil surface suction jets, suction pressure values, and the number of suction slots. Additionally, the study investigates flow reattachments to identify the optimal control case. The results demonstrated that the multiple suction jets along the airfoil blade's upper surface have the best lift coefficient increment performance. In particular, the results showed that maximum improvements in lift coefficient, CL, is attained as 480%, at a stall angle of attack (AOA) equal to 22° and flow speed of 8 m/s using numerical simulation with the suction slot. The experimental results showed that lift coefficient improvements, CL, reached 55.7% using suction holes at a stall AOA equal to 16° and a flow speed of 8 m/s. In addition, the CL, CD, CL/CD, and separation flow are very sensitive to the suction jet location and the use of the multi-suction technique simultaneously.