On the generation and evolution of internal gravity waves
- 1 August 1984
- journal article
- research article
- Published by Cambridge University Press (CUP) in Journal of Fluid Mechanics
- Vol. 145 (-1), 127-149
- https://doi.org/10.1017/s0022112084002846
Abstract
In order to study the tidal generation and evolution of internal waves, both experimentally and theoretically, a two-dimensional two-layer model has been developed. The laboratory model consists of two immiscible fluid layers in a long wave tank, where time-dependent flow can be created by towing a suitably shaped obstacle with a sinusoidal motion. The effects of changing the Froude number and the ratio of the depths of the two fluid layers on the shape of the interface are studied. The first theoretical model considers the motion to be quasi-steady, allowing only a balance between buoyancy and inertial forces, and is in reasonable agreement with the experimental results for very slow motions and the initial phase of the tidal cycle only. A more complete numerical solution is based on the vortex-point method in which the interface is modelled by a set of discrete vortices, while the rigid boundaries, which include the obstacle, are modelled by a source distribution. The resulting governing equations are expressed in Lagrangian form, and the baroclinic generation of vorticity is related to the generation of source density, through two simultaneous integrodifferential equations. For small Froude numbers, the experimental and numerical results are in good quantitative agreement. At large Froude numbers, the numerical solution, which does not consider mixing between the two layers nor boundary-layer separation from the obstacle, gives a slight difference in the position of the maximum interface displacement from that found in the experiment.Keywords
This publication has 10 references indexed in Scilit:
- Generation of internal waves in Massachusetts BayJournal of Geophysical Research: Oceans, 1983
- Vortex simulations of the Rayleigh–Taylor instabilityPhysics of Fluids, 1980
- Internal Solitons in the Andaman SeaScience, 1980
- Tidal interaction of stratified flow with a sill in Knight InletDeep Sea Research Part A. Oceanographic Research Papers, 1980
- A note on the internal solitary waves produced by tidal flow over a three‐dimensional ridgeJournal of Geophysical Research: Oceans, 1979
- The deformation of steep surface waves on water ll. Growth of normal-mode instabilitiesProceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences, 1978
- The generation of long nonlinear internal waves in a weakly stratified shear flowJournal of Geophysical Research, 1974
- On a vortex sheet approach to the numerical calculation of water wavesJournal of Computational Physics, 1973
- Some Aspects of the Flow of Stratified Fluids: II. Experiments with a Two-Fluid SystemTellus A: Dynamic Meteorology and Oceanography, 1954
- The formation of vortices from a surface of discontinuityProceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1931