REPUBLIC OF SERBIA

MINISTRY OF DEFENCE

www.mod.gov.rs

MINISTRY OF DEFENCE

Material Resources Sector

Defensive Technologies Department

Military Technical Institute

www.vti.mod.gov.rs

various methods OF artillery projectiles base drag reduction

MOHAMMED AMIN DALI

University of Defence, Military Academy, Belgrade, Serbia, DaliMA380@gmail.com

Slobodan JARAMAZ

University of Belgrade, Faculty of Mechanical Engineering, Belgrade, Serbia, sjaramaz@mas.bg.ac.rs

Abstract: Since the low pressure in the afterbody region during the projectile’s flight, which is responsible for up to 50% of the total drag, reducing of the base drag is an efficient and practical way to reduce the total drag of projectile. Two methods of base drag reduction are used. The first is to optimize the shape of the projectile (boattailed afterbody, base flow separation and the hollow base projectile). The second method consists of increasing the pressure behind the projectile by base burning; this is accomplished with injection of a low velocity fluid in the recirculation region directly behind the base using the base bleed burning or the external burning. This article is focused on study of various methods of reducing the base drag of artillery projectiles caliber 122mm. The computational fluid dynamics (CFD) numerical simulations (RANS, 2-D axisymmetric configuration) were performed, in order to investigate the base drag characteristics of the projectiles, with various base shapes and different techniques in order to reduce the base drag coefficient at different Mach numbers
(from M = 0,9 to 2,2).

Keywords: Artillery projectiles; CFD; Base drag reduction; Base bleed; Improved boattail.