Unsteady Supersonic Flow of Discharged Projectile from Tube

Unsteady laminar and turbulent supersonic flow of discharged projectile from tube has been numerically simulated. The equations of axisymmetric viscous and compressible flow has been numerically solved by van leer flux vector splitting method, with time and space second order accuracy by using moving boundary. When projectile is discharged from tube the complicated flow in front and back of projectile is created. This flow includes types of expansion and shock waves. Complicated intractions between these waves make analysis of this flow difficult. The numerically simulation could predict expansion wave, bow shock wave in front of projectile, barrel shock wave, mach disk, vortex ring, shear layer well. Results show that, there isn’t difference between both laminar and turbulent flow arrangment, but the aerodynamic forces in both of them (laminar and turbulence) is different. The variation of acceleration and aerodynamic forces, when projectile is discharging from tube, due to more intractions between expansion and shock waves, was very much and caused the vibration of projectile and if it is lightweight, this vibration will change its path. While projectile starts to discharge from tube, the acceleration will be maximum but when the entire of projectile discharges from tube, the resistant force is increased and the acceleration is decreased.