A slender ship moving at a near-critical speed in a shallow channel

Abstract

The problem solved concerns a slender ship moving at a near-critical steady speed in a shallow channel, not necessarily in symmetric configuration, involving the special phenomenon of generation of solitary waves. By using the technique of matched asymptotic expansions along with nonlinear shallow-water wave theory, the problem is reduced to a Kadomtsev–Petviashvili equation in the far field, matched with a nearfield solution obtained by an improved slender-body theory, taking the local wave elevation and longitudinal disturbance velocity into account. The ship can be either fixed or free to squat. Besides wave pattern and wave resistance, the hydrodynamic lift force and trim moment are calculated by pressure integration in the fixed-hull case; running sinkage and trim, by condition of hydrodynamic equilibrium in the free-hull case. The numerical procedure for solving the KP equation consists of a finite-difference method, namely, fractional step algorithm with Crank–Nicolson-like schemes in each half step. Calculated results are compared with several published shipmodel experiments and other theoretical predictions; satisfactory agreement is demonstrated.

Fast Ferry Traffic as a Qualitatively New Forcing Factor of Environmental Processes in Non-Tidal Sea Areas: A Case Study in Tallinn Bay, Baltic Sea

“…It results in much higher wake waves and, accordingly, in much higher wave loads on the coastal environment near the ship lane. Large high-speed craft sailing at specific speeds in shallow areas may produce fundamentally different wave systems than conventional vessels [4,7,36,57]. Ship-generated solitonic disturbances usually have moderate height [70] and possess no immediate danger to the people or to the beach environment.…”

Arbitrary Lagrangian–Eulerian finite element analysis of free surface flow using a velocity–vorticity formulation

“…Flows with free surface find an important place in many engineering applications [30][31][32][33]. Moreover, many numerical schemes for potential flows with fully non-linear free surface boundary conditions are available in the literature [34][35][36].…”

The Optimal Porosity of Stream-Wise Groins for Wave Attenuation Under Different Cross Slope Conditions

“…Therefore, in the present study, CM value was fixed at 2.0 while CD values were determined by numerical calibration with experimental results. b) 2-D model to determine an optimal design of porous structure for wave attenuation The Boussinesq-type equations 10) are solved numerically with a moving ship boundary 11) . Dam et al 12) added the effect of energy dissipation due to wave breaking modeled by introducing eddy viscosity terms (Rbx and Rby).…”

“…The same equations as Chen and Sharma 11) were applied for the boundary condition of a moving ship. The effect of energy dissipation due to wave breaking modeled by introducing eddy viscosity terms Rbx and Rby calculated by using equation as Kennedy et al 13) .…”