Airfoil Design Framework for Optimized Boundary-Layer Integral Parameters

Abstract

An airfoil design framework is introduced in which boundary-layer integral parameters serve as the driving design mechanism. The method consists of generating a parameterized pressure distribution capable of producing the desired boundary-layer characteristics for inverse design use. Additionally, by deduction from the Squire–Young theory, the method allows for the determination of the pressure distribution that results in the minimum theoretical drag. To assess this design framework, several airfoils were developed based on the mission requirements of the RQ-4B Global Hawk aircraft. Numerical results obtained using a viscous-inviscid solver of the integral boundary layer and Euler equations showed that the optimized airfoils achieved profile drag reductions of 9.06 and 6.00%, respectively, for $\alpha =0°$ and $L/D_{\max }$ design points. A validation experimental campaign was also performed using the optimized CA5427-72 airfoil. The acquired data produced the expected pressure distribution characteristics and aerodynamic performance improvements, typifying the efficacy of the design framework.