Aerodynamic Analysis of a Morphing Wing Using Vorticity Based Solver

Abstract

This study addresses an efficient approach to analyzing Variable Camber continuous trailing edge flaps (VCCTEF) wings, which mimics the concept of morphing or shape changing wings. The validation model used in this research is a Boeing 757 based Generic Transport Model (GTM) wing semi-span model with 5 sets of flaps at the trailing edge with each set containing three flap elements in the streamwise direction. These three flaps form the trailing section and trailing edge of the airfoil. The geometry containing the fuselage, main wing and 15 three dimensional flaps is modeled in NASA’s Open Vehicle Sketch Pad (OpenVSP). The unstructured mesh geometry is then exported from VSP and into FlightStream, a vorticity-based solver, for low speed aerodynamic analysis. The deflection of the flaps is achieved in FlightStream with simple x,y,z rotations coupled with x,y,z translations along user defined and reference co-ordinate systems. The analysis results (Cl, Cd) are validated against wind tunnel data for VCCTEF semi span GTM model. Baseline FLAP0 deflection (with all 15 flaps at zero deflection angle) and some cases with flaps deflected at different angles were available in the wind tunnel data set and were modeled in FlightStream. With a successful validation, a generalized analysis of morphing wings was undertaken as a demonstration of the utility of FlightStream and the underlying surface vorticity approach in conceptual design environments. This approach was shown to capture somewhat nuanced design changes with speed and accuracy. In summary, the goal of this work was to validate and illustrate the capability of a surface vorticity approaches to model the aerodynamics of morphing wing geometries in the conceptual and preliminary phase of aircraft design.