Base Bleed projectile simulation for long range large caliber artillery modeling

Abstract

Base Bleed projectile (BB) are artillery projectiles that use base exhaust ejections to reduce the drag that the projectile encounter during its flight. This function is beneficial in extending the range of the artillery projectiles. 20% to 30% drag reduction can be achieved using base bleed unit by relieving between 0.3 - 0.85 of the total base drag force. This can extend the artillery range 30%. To estimate the performance the North Atlantic Treaty Organisation (NATO) established STANAG a Standard Agreement (STANAG) to deal with the organisation standards. For the base bleed simulation problem (STANAG 4355) recommend two methods to be used to determine the base bleed projectile trajectory. These two methods take into consideration several fitting parameters to establish a model to calculate the base bleed projectile trajectory. These parameters need to be adjusted for every firing condition, which make the model expensive to model base bleed behaviour in real life conditions as it requires scaling parameters to be determined experimentally. This is a proposal for a research to develop a new model that can predict base bleed projectiles trajectory with fair accuracy and can predict these trajectories in various firing conditions without the need to obtain specific scaling factors in every specific case. The new modified model will be validated using published work and test data that can be obtain form available resources. (STANAG 4355) has recommended two methods to be used in Base Bleed projectile trajectory calculation. The two methods recommend in STANAG 4355 require considered amounts of fitting parameters. These parameters must be determined from test results and this have a big cost implication. The STANAG models requires fitting parameters for grain temperature and launch elevation to adjust predicted base bleed effect. The objective of this thesis is to establish an alternative trajectory model for the base bleed projectile, based on principle physics and experimental base bleed performance. The new model suggested by this study is validated using test data.