Analysis of Trunk Flutter in an Air Cushion Landing System.

Abstract

This report deals with explaining the occurrence of flutter in the Air Cushion Landing System (ACLS) trunks and suggesting means of suppressing it. Observations of flutter in several ACLS trunks indicate that the flutter is caused by the interaction between the trunk membrane and the flow at the trunk bottom. The flow creates a negative stiffness effect at the bottom which, if larger than the positive stiffness due to the tension of the trunk, induces flutter. A computer simulation based on this model succeeds in predicting the flutter observed in the XC-8A tests. Suggestions on solving the flutter problem are based on either modifying the trunk or modifying the flow. Computer simulations of several suggestions indicate that: (1) Providing a minimum gap (2) Lowering the separation point (3) Changing the operating conditions show good promise in suppressing the flutter. Two other suggestions, not simulated, which also have good potential for flutter suppression are: (1) Incorporating circular trunk (2) Incorporating hybrid trunk. (Author)

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1979
Accession Number
ADA079008

Entities

People

  • Ashok B. Boghani
  • Roger B. Fish

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Air Force
  • Aircrafts
  • Computer Programs
  • Computer Simulations
  • Contracts
  • Elastic Properties
  • Films
  • Flow
  • Flow Fields
  • Fluid Flow
  • Frequency
  • Government Procurement
  • Materials
  • Resonant Frequency
  • Simulations
  • Two Dimensional
  • Vehicle Equipment

Readers

  • Marine Hydrodynamics
  • Structural Dynamics.
  • Systems Analysis and Design