RESEARCH ON ANNULAR NOZZLE TYPE GROUND EFFECT MACHINE OPERATING OVER WATER. ANNULAR DISTRIBUTION OF JET MOMENTUM,

Abstract

The pressure distribution of the jet around the periphery of the annular nozzle of the GEM was measured for various model speeds, clearance heights and air flow rates, and the drag force calculated. It was found that the drag force, although similar to the Havelock solution, was significantly different in two respects. The maximum drag occurred at a lower speed than predicted by the theory, and was approximately proportional to the average base pressure rather than to the square of the base pressure, within the range of variables tested. It was concluded that the wave-making resistance may be transmitted in part to the base by a non-uniform distribution of the jet momentum around the periphery. (Author)

Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1968
Accession Number
AD0668695

Entities

People

  • J. D. Cumming

Organizations

  • University of California, Berkeley

Tags

DTIC Thesaurus Topics

  • Air Flow
  • Annular Nozzles
  • Base Pressure
  • Boundaries
  • Clearances
  • Flow
  • Flow Rate
  • Ground Effect
  • Ground Effect Machines
  • Momentum
  • Nozzles
  • Pressure Distribution
  • Resistance

Readers

  • Aerodynamics.
  • Aerodynamics/Aeronautics.
  • Fluid Dynamics.