Experimental and theoretical research on liquid droplet impact

The erosion data discussed were obtained with a water gun ejecting elongated 1.2-mm-diam water slugs at up to 600 m/sec at a rate of 50 slugs/min. Maximum rate of damage was found to occur at an impact velocity of 480 m/sec, the damage rate decreasing at higher velocities. This is attributed to the fact that, for this device, the shape of the jet leading edge depends on velocity, and changes in the leading-edge shape at higher velocities provide less damage potential. Studies of the influence of the angle of impact, using Plexiglas, soft aluminum, and pure nickel, showed that the damage rate falls rapidly at a fixed velocity as the angle is reduced from perpendicular. High-speed motion picture sequences of jet impact on various materials revealed widely differing splash-back patterns produced by the individual materials. Attempts to correlate splash-back with erosion resistance were unsuccessful; however, the splash patterns do indicate that impacts are accompanied by substantial surface deformation. A computer program was devised to evaluate instantaneous surface deformation under impulsive surface loading.