Experimental investigation of embedded cross-flow fan for airfoil propulsion/circulation control

This experimental study examines the feasibility and effectiveness of using a cross-flow fan embedded in an airfoil for simultaneous propulsion and circulation control. In an earlier CFD study, results indicate that a 34% thick airfoil equipped with a trailing-edge embedded cross-flow fan can operate stall-free up to 40̈ angle of attack and achieve lift coefficients upwards of 6-7. This study seeks to experimentally verify the CFD results and provide further insight into the fan's behavior in providing circulation control to the airfoil. Through flow visualization techniques, surface static pressure, and wake total pressure measurements, the degree to which the fan can influence the flow is determined. Surface pressure distributions are studied for a wide range of fan operating points and angles of attack, leading ultimately to the calculation of the relative improvement in the airfoil's lift coefficient curves for the cases studied. Finally, the experimental setup and geometry was reproduced in the CFD package Fluent for direct comparison with the acquired data. The test results confirm the viability of the proposed Propulsive/Circulation Control airfoil concept.