03.4 - Applied Aerodynamics
HIGH SPEED DRAG REDUCTION OPTIMIZATION FOR PROJECTILES
T. Wan¹, H.-C. Chang¹, C.-M. Liu¹; ¹Tamkang University, China
Drag reduction is one of the important goals for aircraft design or operation, and it is especially true for high speed flight. Here we achieved major drag reduction and gain deeper understanding of the physical phenomenon for high speed vehicles with aerodisk apparatus. Pressure drag stirred by the shock wave is the main challenge of high speed flight, and blunt body is always the principle configuration for high speed flow regime, but it would induce substantial drag. Therefore, aerodisks can be efficiently utilized as a mean for drag reduction. With the newly defined efficiency parameter; the drag reduction amount of all different cases have be calculated and studied. Comparison with the counter-flow jet cases is also included via the same computational tools. In this work, we investigate the effect of different geometric shapes of aerodisks with various disk gap widths on drag reduction. Accordingly, a series of numerical simulation work was implemented to find the behaviour as to high speed flow over aerodisked projectiles. Moreover, the drag reduction efficiency of blunt bodies would be optimized via the Kriging method. For the models studied, we found that the drag on the disked blunt bodies is much lower than the disked off one. The drag reduction efficiency especially would be predominated by the scale of recirculation zone, which increases as both the aerodisk length and the gap size of aerodisk increase. Hence, the performance of drag diminution will depend on the design parameters such as projectile configurations, length, and tip geometric shapes. It appears that the aerodisk gap conception considered in this work can found their practical application in future high speed projectile operation.