Numerical simulations of wave generation by a vertical plunger using RANS and SPH models

The water wave generation by a freely falling rigid body is examined in this paper. Two different two-dimensional numerical approaches have been utilized to simulate the time histories of fluid motion, free surface deformation, and the vertical displacement of a rectangular-shape rigid body. While the first approach is based on the Reynolds-averaged Navier-Stokes (RANS) equations, with the k-ε closure model to compute the turbulence intensity, the second uses the smoothed particle hydrodynamics (SPH) method. Numerical simulations using several different initial elevations of the rigid body and different water depths have been performed. The displacement of the moving rigid body is determined by dynamic equilibrium of the forces acting on the body. Numerical results obtained from both approaches are discussed and compared with experimental data. Images of the free surface profile and falling rigid body recorded from the laboratory tests are compared with numerical results. Good agreement is observed. Numerical solutions for the velocity fields, pressure distributions, and turbulence intensities in the vicinity of the falling rigid body are also presented. The similarity and discrepancy between the solutions obtained by the two approaches are discussed.