Surrogate Modeling and Multi-objective Optimization of ChineForebody for Aerodynamics and Stealth characteristics

Abstract

Chines are sharp edges or longitudinal lines designed for the cross-section of the fuselageor body. Chines in aerodynamics act as a long extension of the wing root along thefuselage. Modern aircraft have chine along its nose section that aligns with engineintakes. Chines produce stronger vortices that interact with leading-edge vortices of thewings to provide maneuvering lift at certain flight conditions. Chines create an obliqueangle for the incoming radar wave which is deflected or scattered away from the receiverof radar which reduces RCS signature. A low RCS enhance stealth or the radar cannotdistinguish the target correctly.In this research, a multi-disciplinary approach of Computational Fluid Dynamics (CFD)and Computational electromagnetics (CEM) is adapted for multidisciplinary design op-timization involving aerodynamics and Radar Cross Section (RCS).Design explorationand optimization techniques are adapted for optimal design consideration of chine fore-body to be used on tactical aircrafts. For design exploration cubic bezier curves wereused to design the back curve of the chine forebody which offer flexibility and degreeof freedom. The cubic bezier curves control points were parameterized which providedCP coordinates as input variables. Using Design of Experiments (DOE) approach theseinput variables provided 31 uniques chine forebody back curve designs. Aerodynamicsparameters which were needed to be optimized were extracted using CFD. Similarly,RCS of each forebody design was extracted. The aerodynamics parameters and RCSserved as response variables. Using Response Surface Method (RSM) each the desiredresponses were optimized which provided an optimal design for chine forebody basedon response variables. The optimization method reduced RCS around 73.30% and dragcoefficient at zero lift 50.24% when compared to baseline forebody design.