Initial stage of an inclined impact of a large solid sphere on a water layer

An inclined impact of a spherical segment with a curvature radius of 106.5 mm onto a water layer 20 mm thick is studied up to the instant of the body–liquid contact. The range of the impact angle with respect to the horizontal plane is 90–15$^\circ$, and the vertical component of velocity for all angles is 10 or 20 mm/s. The measurements are performed by a synthetic schlieren method. The marker displacements are measured by a PTV algorithm. Distributions of the liquid layer thickness in space and time along two horizontal axes are obtained. It is shown that a change in the impact angle does not alter the dynamics of crater deepening and expansion at the initial stage; the crater remains axisymmetric. It is found that the rear slope of the crater becomes steeper in the case with the maximum deviation of the angle from the vertical line, presumably, because of the local decrease in pressure. The characteristics of capillary waves generated by the impact are independent of the impact angle.