Linear generation theory of 2D and 3D periodic internal waves in a viscous stratified fluid

摘要: We investigated analytically and experimentally 2D 3D periodic internal waves generated by small harmonic oscillations of a plate an impermeable vertical cylindrical tube in exponentially stratified viscous fluid. The linearized governing equations were solved integral transform method. exact boundary conditions on the surface body, as well are satisfied if, addition to propagating waves, currents emitting taken into account. On basis these two forms fluid motion, we constructed complete linear theory wave generation, without any external parameters. We calculated amplitudes evolution along beam so-called ‘St. Andrew's Cross’ shape, namely number maxima amplitude cross-section. spatial decay was different problems due geometry. distance from source, where transition bi-modal uni-modal takes place, is defined. Small viscosity smoothes out singularity that arises field inviscid characteristics critical angles. Experimental observations probe measurements pattern confirmed theoretical results for far structure. absolute values differed experimental factor less than 1.5. Indirect evidence Schlieren photographs flow presented. Copyright © 2001 John Wiley & Sons, Ltd.