Experimental Study of LEX Angle Effect on Vortical Flow Over the Diamond Wing with Airfoil-Shaped Section by Using Hot-wire and Five-hole Probe

In this research, the effects of LEX angle on flow pattern over the diamond wing by using hot-wire and five-hole probe are investigated. The pressure coefficient tests over the wing at three different angles of attack respectively 5, 10 and 15 degrees and on two section was conducted by five hole probe. Also turbulence intensity measurements were conducted at three sections for 10 degree angle of attack by using hot wire anemometer. Experimental tests were conducted in a closed circuit wind tunnel with acceptable flow quality at the velocity of 12.5 (m/s) equal to 192500 Reynolds number. At a constant angle of attack with a downward movement the flow; the vortex diameter formed due to the Leading edge of the wing. Therfore, the LEX vortex increased which has led to growing pressure suction on the wing. Amplified suction pressure at the center of the LEX vortex core and the leading edge vortex have carried the two vortices closer together. Thus, the larger the vortex core lead to higher turbulence intensity by moving to downstream. Frequency analysis near the center of the leading edge vortex and Lex vortex showed that at constant section over the wing, the turbulence intensity near vortex core exposed, increasing turbulence intensity that caused to rise the amplitude spectra of fluctuation. Furthermore, frequency analysis indicate that the maximum domain of power spectra increases for LEX angle of 16 degree with rising of angles of attack.