Aerodynamic Shape Optimization of a Missile Using a Multiobjective Genetic Algorithm

Ahmet Şumnu,Orkun Öğücü,İbrahim Halil Güzelbey

doi:10.1155/2020/1528435

Abstract

The aim of this paper is to demonstrate the effects of the shape optimization on the missile performance at supersonic speeds. The N1G missile model shape variation, which decreased its aerodynamic drag and increased its aerodynamic lift at supersonic flow under determined constraints, was numerically investigated. Missile geometry was selected from a literature study for optimization in terms of aerodynamics. Missile aerodynamic coefficient prediction was performed to verify and compare with existing experimental results at supersonic Mach numbers using SST k-omega, realizable k-epsilon, and Spalart-Allmaras turbulence models. In the optimization process, the missile body and fin design parameters need to be estimated to design optimum missile geometry. Lift and drag coefficients were considered objective function. Input and output parameters were collected to obtain design points. Multiobjective Genetic Algorithm (MOGA) was used to optimize missile geometry. The front part of the body, the main body, and tailfins were improved to find an optimum missile model at supersonic speeds. The optimization results showed that a lift-to-drag coefficient ratio, which determines the performance of a missile, was improved about 11-17 percent at supersonic Mach numbers.

Highlights

There are many variants of missiles specialized for different purposes from short-range cruise types to intercontinental ballistic ones, the flight performance criteria used to measure their effectiveness are common: range, speed, and maneuverability
The results showed that the aerodynamic drag was decreased about 20% using the best variation when the framework of RANS was compared with the Sears-Haack body
The Computational Fluid Dynamics (CFD) solution results observed that these three turbulence models which are SST k-omega, realizable k-epsilon, and Spalart-Allmaras were in good agreement with the experimental results

Summary

Introduction

There are many variants of missiles specialized for different purposes from short-range cruise types to intercontinental ballistic ones, the flight performance criteria used to measure their effectiveness are common: range, speed, and maneuverability. The third approach has high computational complexity due to the requirements to solve the coupled nonlinear partial differential equations resulting from the interactions of fluid with surfaces. In the aviation engineering field where shaped surfaces are investigated at subsonic or supersonic flow, some assumption loses its validity due to the separation, reattachment, eddies, vortex formation, and vortex shedding phenomenon arising from adverse pressure gradient, boundary layer growth, and circulation. Solving the decomposed RANS equations instead of Navier-Stokes equations reduces the computational requirements and makes it possible to simulate practical engineering flows for complex models [2]. The comparative studies from the related literature that utilize the experimental data and simulations results show that the solutions obtained by RANS models are International Journal of Aerospace Engineering appropriate to use in a shape optimization process of a missile as explained as follows

Methods

Results

Conclusion