Accession Number:

AD0775624

Title:

Vibratory Dynamics of Flow-Excited Struts in Water

Descriptive Note:

Final rept.

Corporate Author:

DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD SHIP ACOUSTICS DEPT

Personal Author(s):

Report Date:

1973-12-01

Pagination or Media Count:

77.0

Abstract:

The general problem of the response of a cantilevered beam to flow over its surface is considered experimentally and theoretically. The measured flow induced modal vibratory motion of a nonsinging beam is compared to theoretical estimates of inflow turbulence excitation and boundary-layer excitation. The comparison indicates that while the response to turbulent inflow is dominant at low frequencies, the response of the strut to its own boundary layer is important at high frequencies. The magnitude of hydrodynamically induced damping is also characterized experimentally. It is shown that results agree favorably with an approximate expression based on finite-aspect-ratio, unsteady airfoil theory. Loss factors, based on entrained mass, are found to be inversely proportional to a reduced frequency based on the width of the strut and inflow speed. Finally, a wind tunnel study of the statistical properties of the boundary layer formed on the strut is described. Modified author abstract

Subject Categories:

  • Marine Engineering
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE