Accession Number : ADA298293

Title :   Selected Topics in Coastal and Ocean Technology.

Descriptive Note : Final rept. 1 Oct 90-30 Sep 94,

Corporate Author : SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA

Personal Author(s) : Jenkins, Scott A.

PDF Url : ADA298293

Report Date : 01 AUG 1995

Pagination or Media Count : 114

Abstract : This final report details research in three major areas: (1) sedimentation control in harbors and waterways. (2) wave structure interaction for a novel tetrahedron sandbag structural concept and (3) tactical oceanography involving development of an optimum glide theory for low speed submarine operations. The sedimentation control research focused on understanding the mechanics of bed shear strength and explored new methods to elevate the bottom shear stress to induce erosion of the bed and prevent deposition. The bed shear strength was found to be monotonic functions of concentration, organic content and salinity. Means for enhancing the shear stress on the bed were studied in both a laboratory flume and in field installations. Both active and passive measures were evaluated. Active measures for enhancing bed shear stress included arrays of bottom mounted jets powered by a centrally located pump and ducted propellers powered by remote hydraulic power supplies. Passive measures invoked arrays of near bottom moored wings whose vortex wakes in tidal flow eroded and resuspended bed sediments. The wave structure interaction research involved development of a tactical break water concept constructed of tetrahedron sandbags filled in situ by pumping sand slurries into the bags using the available sea floor sediments. The bags were not placed individually, but dropped to the sea floor to form talus piles. Arrangements of talus piles in parallel and V-shaped bars were developed to produce Bragg scattering patterns that could be made to either constructively or destructively interfere with incoming waves. (MM)

Descriptors :   *OCEAN WAVES, *SEDIMENT TRANSPORT, *WAKE, *COASTAL ENGINEERING, *MARINE PROPELLERS, *OCEAN BOTTOM SOILS, *SEDIMENTATION, *MILITARY OCEANOGRAPHY, SYMPOSIA, COASTAL REGIONS, INTERACTIONS, SAND, VORTICES, TIDAL CURRENTS, SLURRIES, SHEAR STRESSES, SALINITY, SOIL EROSION, WINGS, SUBMARINES, DREDGING, JET FLOW, HARBORS, WAVES, WORKSHOPS, WATERWAYS, HYDRAULIC POWER, BRAGG SCATTERING, MOORING, SHEAR STRENGTH, WATER JETS, SHROUDED PROPELLERS.

Subject Categories : Physical and Dynamic Oceanography
      Civil Engineering
      Submarine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE