OBLIQUE HIGH-SPEED LIQUID-SOLID IMPACT

The classical oblique high-speed liquid-solid impact problem has been studied in this paper. The effect of the impact angle on the side jetting velocity has been photographed using Imcon high-speed camera (frame rate up to one million frames per second). The maximum downward side jetting velocity occurs at a 15-degrees-20-degrees impact angle. The shock wave in liquid drops and stress waves in solids under oblique impact are observed by Imcon schlieren optics and polariscope optics. The strength of shock waves in liquid drops is reduced as the impact angle increases. When the impact angle is large enough, side jetting no longer appears. The deformation of the liquid drop at this time is similar to incompressible fluid flow. The variation of the impact pressure with the impact angle is analyzed by high-speed photography and damage tests of materials. The liquid impact erosion of polycarbonate (PC) and polymethylmethacrylate (PMMA) by single and multiple impacts is examined in detail. The variation of the erosion area with impact angle is found to be in general compliance with the relationship between the side jetting velocity and impact angle. For PMMA material, the maximum weight loss occurs at the impact angle of 15-degrees in single impact; but in multiple impacts, the maximum weight loss is at normal impact. For PC material, the maximum erosion depth still occurs with normal impact.