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

Effect of base bleed on the drag reduction

HABIB BELAIDOUNI

Military Academy, University of Defense, Belgrade, h_belaidouni@yahoo.fr

SAŠA ŽIVKOVIĆ

Military Technical Institute, Belgrade, sasavite@yahoo.com

MIRKO KOZIĆ

Military Technical Institute, Belgrade, mkozic@open.telekom.rs

MARIJA SAMARDŽIĆ

Military Technical Institute, Belgrade, majasam@ptt.rs

BOUTEMDJET ABDELWAHID

Military Academy, University of Defense, Belgrade, abdelwahed1954@gmail.com

Abstract: One of the most important aerodynamic performance characteristics for the artillery projectile’s shell is the total drag. The total drag of projectile can be divided into three components consisted of pressure drag, viscous drag, and the base drag. The base drag is major contributor to the total drag, for that reason it’s important to have its good estimation in the preliminary design stage of a projectile. Projectiles with base bleed use concept of reducing base drag, by injection of gas generated by burning of composite propellant, into the base area. In the paper, the internal ballistic calculation of existing base bleed configuration is presented. Using CFD computations various turbulence models were tested. The numerical results were compared and validated with semi empirical theory. Obtained numerical results with the most appropriate turbulence model served in further CFD calculation of aerodynamic drag of the projectile with and without base bleed effect.

Keywords: Base drag, Base bleed, Computational fluid dynamics.