Accession Number:

AD0657013

Title:

A STUDY OF THE CHARACTERISTICS OF TRANSONIC BUFFET PRESSURES ON A LARGE HAMMERHEAD CONFIGURATION,

Descriptive Note:

Corporate Author:

AEROSPACE CORP EL SEGUNDO CALIF TECHNICAL OPERATIONS

Personal Author(s):

Report Date:

1967-06-01

Pagination or Media Count:

89.0

Abstract:

The transonic fluctuating pressures over a large hammerhead configuration are investigated. The study examines existing experimental data on other configurations, presents fluid-mechanical arguments, derives a number of concepts and scaling parameters, and finally makes estimates of the fluctuating pressure characteristics for a large hammerhead configuration. The significant findings are as follows 1 All the fluctuating pressure fields examined seem to indicate a strong influence of a square-wave type of random fluctuation in the low-frequency region 2 A square-wave type of pressure fluctuation can arise from the random oscillation of the separation point because of stream-wise disturbances or cross-stream disturbances, or from the intermittency of a free boundary 3 In a narrow range of high subsonic Mach numbers, a periodic modulation of the random pressure fluctuation can arise from shock-wave oscillation. 4 The turbulence field seems to have a memory - a short one at least. 5 The large eddies in the turbulence field apparently dominate the statistical properties 6 The magnitude of the fluctuating pressures seems to be linearly dependent upon the mixing region or shear layer thickness and can be enhanced by a positive pressure gradient. 7 The unsteadiness of the separation surface behind the backward-facing step of a hammerhead configuration can be visualized as a series of teeter-totters lined up side-by-side around the perimeter and randomly going up-and-down. Thus, a revolving motion of the hammerhead about the flow axis might be induced. Author

Subject Categories:

  • Aerodynamics
  • Fluid Mechanics
  • Ground Support Systems and Facilities for Space Vehicles

Distribution Statement:

APPROVED FOR PUBLIC RELEASE