Linear theory for single and double flap wavemakers

Abstract: In this paper, we are concerned with deterministic wave generation in a hydrodynamic laboratory. A linear wavemaker theory is developed based on the fully dispersive water wave equations. The governing field equation is the Laplace equation for potential flow with several boundary conditions: the dynamic and kinematic boundary condition at the free surface, the lateral boundary condition at the wavemaker and the bottom boundary condition. In this work, we consider both single-flap and double-flap wavemakers. The velocity potential and surface wave elevation are derived, and the relation between the propagating wave height and wavemaker stroke is formulated. This formulation is then used to find how to operate the wavemaker in an efficient way to generate the desired propagating waves with minimal disturbances near the wavemaker.