ON THE APPLICABILITY ASSESSMENT OF VON KARMAN’S MOMENTUM THEORY IN PREDICTING THE WATER-ENTER LOAD OF V-SHAPED BODY

The water landing motion of an amphibious aircraft is a complicated problem, that can lead to uncomfortable riding situation and structural damage due to large vertical accelerations followed by sorts of dynamic responses. The problem is here investigated by solving unsteady incompressible Reynolds-averaged Navier-Stokes equations enclosed by the standard k-ω turbulence model. The theoretical solutions established by the momentum theory are also employed. In order to validate the relationships between initial vertical velocity and peak value of vertical acceleration, a free fall test case of 2D symmetric wedge oblique entry is presented first. Then, the quantitative relations are investigated to water landing event of a 3D cabin section extracting from an amphibious aircraft. Detailed results through the free surface and pressure distribution are provided to show the slamming effects, and their physical implications are discussed. The result shows that a linear function of maximal acceleration to the square of initial vertical velocity can be built up for all cases, contributing to variation prediction of acceleration.