Experimental Study of Internal Gravity Waves Over a Slope.
Abstract
Propagation of internal gravity waves over a slope in a fluid with constant Brunt-Vaisala frequency was studied in a wave tank. Wave motion in the fluid interior was measured with conductivity probes, and in the boundary layer, with dye streaks and neutrally buoyant particles. Outside the breaking zone, the amplitude and horizontal wave number of high-frequency waves increase linearly with decreasing depth; this is in agreement with existing linear, inviscid solutions. Well upslope, a zone of breaking or runup is produced by the high-frequency waves. If the wave characteristics are closely parallel to the bottom slope, upslope propagation of low-frequency waves produces a line of regularly spaced vortices along the slope, which slowly penetrate into the fluid interior; mixing in these vortices sets up thin horizontal laminae that are more nearly homogeneous than adjacent layers. A criterion for incipient motion of bottom sediment under shoaling internal waves was developed using available theoretical solutions for velocity in the viscous boundary layer, found to be valid for certain experimental conditions. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1970
- Accession Number
- AD0717367
Entities
People
- David A. Cacchione
Organizations
- Massachusetts Institute of Technology