Accession Number:

AD0689202

Title:

AN EXPERIMENTAL INVESTIGATION OF THE TURBULENT CHARACTERISTICS OF A BOUNDARY LAYER FLOW OVER A VIBRATING PLATE,

Descriptive Note:

Corporate Author:

GENERAL DYNAMICS CORP GROTON CONN ELECTRIC BOAT DIV

Personal Author(s):

Report Date:

1969-05-01

Pagination or Media Count:

32.0

Abstract:

Measurements of the spectral density of the axial component of turbulent velocity were made in a boundary layer when the surface beneath it was vibrating in a deterministic manner. These measurements indicated that a narrow-band disturbance resulted from the plate motion. The spectral density of the axial turbulent velocity, at the surface excitation frequency, exhibited a marked increase in magnitude when the surface was being excited. The ratio of the spectral density with and without plate excitation was measured throughout the boundary layer within the region of the vibrating surface. These measurements indicated that the disturbance produced by the surface motion is convected downstream where it is reinforced if it comes into a region which is influenced by a portion of the plate that has an amplitude of vibration greater than the upstream portion. This reinforcement phenomenon was observed for every test condition in which the test plate excitation was a mode where two or more displacement crests appeared in the longitudinal direction. Observations of the transverse variation of the disturbance conclude that there is an absence of any transverse convection nature. Author

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE