On the Vertical Momentum of the Fountain Produced by Multi-Jet Vertical Impingement on a Flat Ground Plane.

Abstract

An analysis of the vertical momentum flux for the fountain produced by multi-jet vertical impingement on a flat ground plane is presented. The jets are considered to have equal thrust and the same exit diameter, and to be equally-spaced on a bolt circle. Analytical formulas for both the core and arms of the fountain have been derived, and show the dependence on the height, planform size, and number of jets. Preliminary numerical comparison with some experimental data indicates the formulas to be capable to produce acceptable predictions. Comparison has also been made with Kuhn's empirical formulas, revealing some similarity as well as differences between the two sets of formulas. Additional work needed for the development of prediction methods for lift losses is suggested. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 1979
Accession Number
ADA082765

Entities

People

  • K. T. Yen

Organizations

  • Naval Air Warfare Center Warminster

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Abstracts
  • Aerodynamics
  • Aircrafts
  • Classification
  • Databases
  • Diameters
  • Engineering
  • Equations
  • Experimental Data
  • Ground Effect
  • Hovering
  • Measurement
  • Momentum
  • Numbers
  • Planform
  • Reflection
  • Short Takeoff Aircraft

Readers

  • Aerodynamics/Aeronautics.
  • Fluid Mechanics and Fluid Dynamics.
  • Graph Algorithms and Convex Optimization.

Technology Areas

  • Space
  • Space - Hall-Effect Thruster