Aerodynamic Analysis and Optimization of Embedded Slot for Smooth Morphing Trailing Edge

Abstract

Smooth morphing trailing edge (SMTE) has been receiving more attention as a new wing design concept in the past few years due to its high potential in reducing cruise drag, structural weight, aerodynamic noise, and fuel consumption. Apart from the necessity of using new flexible materials and compact actuation mechanisms, it is also faced with the challenge of providing sufficient lift as conventional high-lift devices did during low-speed flight phases. Insufficient low-speed aerodynamics could compromise aircraft takeoff and landing performance. In light of this, a concept of the embedded slot is proposed for use with SMTE. To study the full benefits of the embedded slot, constrained single-objective optimization is first conducted on a two-dimensional airfoil using kriging surrogate models built from Reynolds-averaged Navier–Stokes solutions. The final optimal results show that the maximum lift coefficient from SMTE with a slot is only slightly lower than that of a typical three-element Fowler flap. The parametric analysis showed the strong coupling effects on the aerodynamic performance of slot entry and exit geometry dimensions. Based on the optimal two-dimensional slot design, computer-aided design models of three-dimensional SMTE configurations are built and analyzed. Comparisons among High-Lift Common Research Model SMTEs with and without slot show that the embedded slot improved high-lift performance. After introducing the embedded slot, the maximum lift coefficient for SMTE is raised by 7.9% from 2.277 to 2.457, and the stall angle is increased by 2 deg. This is in comparison with the maximum lift coefficient of 2.572 for the conventional Common Research Model Fowler flap configuration. The results demonstrated the benefits of introducing embedded slot into SMTE for future high-lift designs.