Experimental Investigation of the Velocity Profiles and Turbulence Intensity Wake of S823 Airfoil at Different Reynolds and Angles of Attack

In this study, the blade cross-section profile of horizontal wind turbine (NREL type) is investigated in the wind tunnel. In order to measure the velocity and turbulence intensity the hotwire anemometer is used. The tests are done in the wake of the S823 airfoil at velocities of 5, 7 and 12 m/s and at angles of attack of 0°, 7°, 10°, 13° and 15° and at stations of = , , ,1,2,3. The effects of variation of angles of attack and Reynolds numbers are investigated on velocity defect, additional flow, velocity distribution and turbulence intensity and the curves of effects of changing the downstream position on the velocity distribution are presented. The results show that the additional velocity in the near of the trailing edge of airfoil is great and increasing the angles of attack increase the additional velocity and increasing the Reynolds numbers decrease the additional velocity and also asymmetric wake of mean velocity profile and increasing region of the mean velocity profile at lager attack angle than 10° can as sign of vorticity developed at region of wake airfoil.