Accession Number:

ADA202674

Title:

Analysis of Propeller Wake Flow Visualization Near a Free Surface

Descriptive Note:

Technical rept. Jan-Sep 1988

Corporate Author:

DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP HYDROMECHANICS DEPT

Personal Author(s):

Report Date:

1988-11-01

Pagination or Media Count:

37.0

Abstract:

Propeller wake flow visualization was carried out for several depths of submergence below a free surface. The wake was visualized by laser light sheet illumination of the blade tip vortex helix seeded with fluorescein dye. Effects of the free surface on the propeller wake were seen at the shallower submergence depths. Instability in the helix was apparent at much shorter distances downstream than has previously been observed in cavitation experiments. The dominant cause of this instability is determined to be caused by the use of inclined universal joints in the propeller drive system. A simple test modification is described for the elimination of this influence. Estimation of Reynolds number, submergence depth, and propeller loading influences on the propeller wake are given. Keywords Marine propellers wake, Vortex kinematics, Flow visualization.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE