Circulation Measurements About a Rapidly Pitching Airfoil Using an Ultrasonic System26th AIAA Fluid Dynamics Conference: San Diego, CA
AbstractAn ultrasonic system was developed to measure the circulation about a sinusoidally pitching NACA 4418 airfoil. The system consisted of two opposing ultrasonic ranging modules arranged such that the differences between the sound propagation times in opposite directions could be related to the instantaneous circulation. For the stationary airfoil, the measured lift coefficient was within 5% of the tabulated data while the observed stall angle was 2° less than the tabulated value. Measured hysteresis loops verified the applicability of the ultrasonic system to the dynamic stall problem. Measured maximum lift coefficients increased linearly with reduced frequency up to a value of 0.05. Beyond this value, a slower increase of maximum CL with reduced frequency was observed. Nomenclature coefficients are primarily dependent on the angle of observed.
Citation InformationF. J. Weber, Jr., William W. Durgin and H. Johari. "Circulation Measurements About a Rapidly Pitching Airfoil Using an Ultrasonic System" 26th AIAA Fluid Dynamics Conference: San Diego, CA (1995) p. 1 - 11
Available at: http://works.bepress.com/wdurgin/55/