On the effect of dense fluid on structures during impact

The dynamical behaviour of impacting structures may be affected by the presence of a dense fluid. This paper investigates the forces exerted by the fluid based on a simple analytical model which refers to a liquid film squeezed by a pair of parallel flat and rigid surfaces. The forces are then introduced in a computer code for calculating the motion of impacting structures. Such calculations will be compared to experimental tests. At this respect encouraging preliminary results were obtained. (orig.)