Journal of Applied Mathematics and Physics, 2014, 2, 277-283

Published Online May 2014 in SciRes. http://www.scirp.org/journal/jamp

http://dx.doi.org/10.4236/jamp.2014.26033

How to cite this paper: Wessam, M.E., Chen, Z.H. and Huang, Z.G. (2014) Flow Field Investigation around Body Tail Projec-

tile. Journal of Applied Mathematics and Physics, 2, 277-283. http://dx.doi.org/10.4236/jamp.2014.26033

Flow Field Investigation around Body Tail

Projectile

Mahfouz Elnaggar Wessam, Zhihua Chen*, Zhengui Huang

Key Laboratory of Transient Physics, NUST, Nanjing 210094, Jiangsu, China

Email: *chenzh@mail.njust.edu.cn, 1851924502@q q.co m

Received February 2014

Abstract

The unsteady compressible flow around a 50 mm projectile governed by the Navier-Stocks (NS)

equation is numerically solved with a Large Eddy Simulation (LES) method, with the Sub-Grid

Scale (SGS) solved by Smagorinsky-Lilly model. The computed results are obtained in supersonic

flow regime for a viscous fluid in order to determine the aerodynamic coefficients with different

angles of attack. The flow around a body tail projectile was solved as a three-dimensional flow.

Keywords

Body Tail Projectile, Aerodynamic Coefficients, Viscosit y, Flow Field

1. Introduction

The flow around a projectile presents turbulent boundary layers, whose separation is a usual phenomena and a

large turbulent wake formed at the bottom of the object. In ballistic aerodynamics, prevention or control of the

separation of the boundary layer is one of the most important aims, as well as an appropriate ogive design [1] [2].

As it is well known, a turbulent flow carries irregular and fluctuating fluid motions which contribute signifi-

cantly to the transport phenomena. They are always three-dimensional, unsteady and mainly irregular except

perhaps by coherent structures, which are as some kind of organized flow motion that can be recognized in the

instantaneous flow fields as well as in the time-averaged ones [3]. There are also eddies with a wide spectrum of

sizes, from the larger ones close to the flow domain ones, to the much smaller ones at which viscous dissipation

takes place. The numerical techniques available in Computational Fluid Dynamics (CFD) to simulate them can

be split in three main types [4] [5].

i) Direct Numerical Simulation (DNS)

ii) Large Eddy Simulation (LES)

iii) Re ynolds-Averaged Navier-Stokes (RANS)

A LES model is chosen since the Re number range to be considered indicates that the flow is fully turbulent.

Its adoption responds mainly to the computed large-scales, associated to the coherent structures developed due

to the projectile motion. As already stated, the smaller scales are not solved but they are modeled, regarding that

its influence over other scales is related to energy transfers [6]. In this work, the CFD is applied to determine the

aerodynamic coefficients by using a commercial CFD code called FLUENT which solves the governing equa-

*