03.1 - Aerodynamics – CFD Methods and Validation
BOUNDARY-LAYER SUCTION AND AERODYNAMIC SHAPE OPTIMIZATION FOR HYBRID LAMINAR FLOW CONTROL ON A FIN
H. Wu¹, W. Song¹, H. Nie¹, Z. Han¹; ¹National Key Laboratory of Aircraft Configuration Design, China
Aerodynamic drag reduction is conducive to improving the economy and environmental friendliness of transport aircrafts, and is of great significance to achieving green aviation. Application of hybrid laminar flow control (HLFC) system on fins has been proved of great potentials in drag reduction. To achieve drag reduction, the HLFC system has to attenuate the Tollimien-Schlichting (TS) and crossflow (CF) instabilities inside the boundary layers and delay flow transition, which requires coupled design of suction parameters and aerodynamic shape. For this purpose, a surrogate-based optimization framework is utilized toward the boundary-layer suction and airfoil shapes on a vertical fin. The optimization toolbox is an in-house software SurroOpt. The aerodynamic characteristics of the fin under HLFC are also evaluated by an in-house software PMNS3DR with automatic transition prediction by an eN method. Results show that the CF instabilities are mainly suppressed by boundary layer suction, and the TS instabilities are suppressed by a favorable pressure gradient introduced through shape optimization. Compared to the baseline configuration, the optimized vertical fin reaches a larger laminar flow range of approximately 55% over the fin surface, bringing a drag reduction by 41.7%, which indicates the effectiveness of the coupled design optimization method for HLFC.