| In this project, an attempt to calculate the characteristics of compressible gas flow around a projectile during the motion of the projectile in the gun barrel is undertaken. The flow is considered axisymmetrical, nonstationary, nonisothermal, compressible, and turbulent. For calculating the compressible gas flow around a projectile, the finite volume method was employed. An h-adaptive mesh refinement scheme based on elemental flow feature gradients is utilized for greater solution accuracy. For modeling flow around the moving projectile both sliding and dynamic meshes were used.; The application of the calculations is in support of the Joint Actinide Shock Physics Experimental Research (JASPER). The JASPER facility utilizes a two-stage light gas gun to conduct equation of state experiments. The gun has a launch tube bore diameter of 28 mm, and is capable of launching projectiles at a velocity of 7.4 km/s using compressed hydrogen as a propellant. A numerical study is conducted to determine what effects, if any, launch tube exit geometry changes have on attitude of the projectile in flight. A comparison of two launch tube exit geometries is considered. The first case is standard muzzle geometry where the wall of the bore and the outer surface of the launch tube form a 90 degree angle. The second case includes a 26.6 degree bevel transition from the wall of the bore to the outer surface of the launch tube. For both cases, solutions are calculated for several positions downstream of the launch tube exit. The effect of beveled muzzle geometry on flight attitude of projectile is studied by using numerical modeling and results are compared with standard design, which is 90° of exit angle. (Abstract shortened by UMI.)... |
