10.12.2023
Abstract
This study focuses on experimental investigation of three different morphing wing planforms and a baseline wing planform using commercial CFD software and load cell measurements in a wind tunnel for the validation of an optimization code developed separately [1]. The wing planforms of interest originate from an optimization code that minimizes drag for a required lift utilizing a 3-D panel method with a 2-D boundary layer solver. The optimization method is gradient based. The first planform of interest is the planform for optimized drag subject to 14 m/s freestream velocity with constraints for physical dimensions and taper ratio. The second and third planforms are generated using the first planform as baseline and optimizing the drag with constant lift subjected to 10 m/s and 16.5 m/s freestream velocity, respectively. In this optimization part, airfoil physical thickness allowances are introduced as inequality constraints to the design process. Wing configurations as outputs of the design tool are tested in the low speed wind tunnel by 6-axes high precision load cell to validate and compare the calculated aerodynamic forces. In the wind tunnel experiments, laminar bubble separation has been encountered. Besides, deviation of experimental and theoretical lift and drag curves were observed for Reynolds numbers below 60 000. Experimental results for each wing configuration nevertheless serve their purpose by drag minimization at the given velocities even though they do not exactly agree with the CFD and theoretical data.