4th Global Engineering, Science and Technology Conference Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet by Md. Tarique Hasan Khan, Department of Mechanical Engineering Wayne State University, USA & Sudipta Saha, Department of Mechanical Engineering Bangladesh University of Engineering and Technology, Bangladesh

OBJECT OF THE PAPER Numerical Simulation of a Paraboloid-tip Bullet Aerodynamic characteristic analysis Closer look on pressure and velocity contour Stream line across the bullet Vortex formation along the trailing edge Static pressure and velocity distribution Identification and analysis of sonic boom creation Study on Pressure drag and wake formation Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

BULLET Projectile propelled by a firearm Does not contain explosives Damage is done by indentation or penetration Generation of Shockwave Creation of Low Pressure Drag and Sonic Boom Different types of Bullet

PARABOLOID-TIP BULLET Fired from a .38 super automatic pistol cartridge Tip is Paraboloid Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

PARABOLOID-TIP BULLET – Some Facts and Figures Designed by Georg Luger and introduced in 1902 by the German weapons manufacturer Deutsche Waffen- und Munitionsfabriken (DWM) World's most popular and widely used military handgun cartridge 60% of police in the U.S. use this cartridge Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

PARABOLOID-TIP BULLET - Specification 9x19mm Paraboloid (abbreviated 9mm, 9x19mm or 9x19) Also known as The 9×19mm Parabellum The specifications for the bullet are as follows: Bullet Diameter, d =9.03 mm Bullet length, l =10.54 mm. Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

PARABOLOID-TIP BULLET - Specification Our interest lies here only into the leading part of the bullet of which experiences various aerodynamic properties Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Numerical Simulation Model Development: Gambit Simulation: Fluent Mesh type: Quadrilateral Structured Mesh along the Straight portion Curved Structured Mesh along the curved portion Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Meshing of total contour Meshing of total contour with bullet (closer view) Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Numerical Methodology Basic Equation: Nutonian Fluid Equations Bullet Velocity: 1350 ft/s Mach Number: 1.21 Flow: Steady, Supersonic, Compressible and Inviscid Inlet Boundary: Pressure 1 atm, Temperature 300k Since the flow is supersonic compressible, a density-based algorithm was used for numerical solution. Gravitational Effect is neglected Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Pressure contour of the continuum and bullet Stagnation Pressure: 243000 Pa Bow Shock wave Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Velocity contour of the continuum and bullet Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Prandtl Mayer Expansion Fan process In supersonic flows, expansion is achieved through an expansion fan called Prandtl Mayer Expansion Fan Across the expansion fan, the flow accelerates (velocity increases) and the Mach number increases Static pressure, Temperature and Density decrease The leading edge of the object causes a shock and the trailing edge causes an expansion Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Prandtl Mayer Expansion Fan process (Contd.) Pressure Contour: The angle through which the flow has turned by expansion fan process Dramatic reduction in pressure Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Prandtl Mayer Expansion Fan process (Contd.) Velocity Contour: The angle through which the flow has turned by expansion fan process Flow accelerates in the same direction and through the same angle (velocity increases) Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Prandtl Mayer Expansion Fan process (Contd.) Static Temperature of flow past the bullet profile The angle through which the flow has turned by expansion fan process Decrease in Temperature Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Prandtl Mayer Expansion Fan process (Contd.) Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Vortex: It is the region in the flow where fluid is spinning about an imaginary axis Wake: It is region of disturbed flow at downstream Pressure Drag: Type of drag caused by difference in air pressure between the leading and trailing side of an object Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Vortex, Wake and Pressure Drag Vortex is formed Small wake area: Due to parabolic geometry Due to wake formation, pressure decreases to about 30000 Pa and velocity rises to about 300 to 380 m/s Total drag coefficient was found to be 0.0111, which indicates low-pressure drag due to small wake area Streamline across the bullet Vortex formation along the trailing edge of bullet Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Post-processing analysis and Result Graphical Representation Static pressure distribution on bullet surface Velocity distribution across the bullet surface This can be explained from Bernoulli’s Equation Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Conclusion Bow shock wave Low pressure drag Small wake formation High Stagnation Pressure Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Further Recommendation No gravitational effect has been considered As Mach Number>1, it was assumed to be inviscid flow. No matter how fast the airflow is, there is always a viscosity effect. So, the results may be a little deviated from the actual one. Further research on other types of bullets ( e.i sharp tip bullet, spherical tip bullet etc.) taking gravitational and viscous effect in consideration is recommended. Numerical Simulation and aerodynamic characteristic analysis of a Paraboloid-tip Bullet

Thank You