THE EFFECTIVE POROSITY OF PARACHUTE CLOTH.

Abstract

Stability, drag, and opening characteristics of solid cloth parachutes change with altitude. Similar changes can be observed at a given altitude when the air permeability or porosity of the cloth is being varied. In this study it is shown that the porosity of a given cloth changes effectively with the density and the compressibility of the air. The effective porosity is related to Reynolds and Mach numbers and it was found that the flow of the air through the cloth is in general turbulent but may approach under certain circumstances a laminar flow character. Tables and graphs showing the effective porosity of four common types of parachute cloth and of one type of a perlon screen with 45% geometric porosity, as well as equations and coefficients which permit under certain simplifying assumptions the calculation of the effective porosity are presented. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1966
Accession Number
AD0479786

Entities

People

  • Helmut G. Heinrich

Organizations

  • University of Minnesota

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Aerodynamic Characteristics
  • Air Force
  • Air Resistance
  • Altitude
  • Computational Fluid Dynamics
  • Equations
  • Flow
  • Flow Rate
  • Fluid Dynamics
  • Free Stream
  • Mach Number
  • Materials
  • Mechanics
  • Reynolds Number
  • Sea Level
  • Tensile Strength
  • Turbulent Flow

Readers

  • Aerial Delivery - Logistics and Supply Chain Management.
  • Aerodynamics/Aeronautics.
  • Systems Analysis and Design