Accession Number : ADA183563

Title :   Observations of Ship Wakes from Space-Shuttle Missions.

Descriptive Note : Final rept.,

Corporate Author : ORI INC ARLINGTON VA

Personal Author(s) : Witting, James M ; Hoglund, Richard F

PDF Url : ADA183563

Report Date : 12 Jun 1987

Pagination or Media Count : 72

Abstract : Highly visible features on the ocean surface behind a moving ship are the Kelvin waves, which appear as a regular pattern moving with the ship, and a ribbon trailing the ship's stern marked by less choppy water than the surrounding, which is produced by the ship's turbulent wake. The simplest analysis of ship waves that derives a basically correct wave pattern is linear water wave theory with a moving steady source. The elevation of the water surface from a simple source moving in a straight line at constant speed is shown. Waves can exist only in the region between + or - inverse (1/3) = + or - 19.47 deg of the center line. On the edges of the pattern the waves form a cusp; their amplitudes are generally at a maximum just inside the cusp lines. The geometry locating wave crests notes that two distinct branches show up, one composed of waves traveling at relatively small angles to the ship direction (the transverse pattern), the other composed of waves traveling at relatively large angles to the ship direction (the divergent pattern). At the cusp line there is a 90 deg phase shift between the two patterns, a feature not shown in most corresponding figures.

Descriptors :   *WAKE, *OCEAN WAVES, PATTERNS, ELEVATION, VELOCITY, MOTION, SHIPS, SHIP STERNS, EDGES, ANGLES, LINEARITY, THEORY, WATER WAVES, WAVES, SOURCES, STEADY STATE, SPACE MISSIONS, SURFACE WAVES, HEIGHT, PHASE SHIFT, SPACE SHUTTLES, TURBULENCE, TRANSVERSE

Subject Categories : Fluid Mechanics
      Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE