Approximate Boundary Layer Methods for a Fast Mid-Fidelity Aerodynamics Code for Helicopter Simulations

Abstract

In order to estimate boundary layer properties and flow separation within the mid-fidelity aerodynamics code UPM, fast, simple, and robust methods are required. Following a review of suitable methods, two approaches were selected and implemented: stripwise analysis using integral boundary layer methods for lifting surfaces and a simplified analysis based on flat-plate analogy for arbitrary non-lifting bodies. The implemented methods were validated for airfoil, wing, fuselage, and rotor simulations. The results show that the implemented methods accomplish the original purpose of estimating friction forces for bodies in attached flows and detecting regions probably dominated by flow separations. However, they neither model detached flows nor predict their impact on body forces and moments.