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-
*