Accession Number : ADA135731

Title :   Causes and Corrections for Propeller-Excited Airborne Noise on a Naval Auxiliary Oiler.

Descriptive Note : Research and development rept.,

Corporate Author : DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD SHIP PERFORMANCE DEPT

Personal Author(s) : Wilson,M B ; McCallum,D N ; Boswell,R J ; Bernhard,D D ; Chase,A B

PDF Url : ADA135731

Report Date : Nov 1983

Pagination or Media Count : 59

Abstract : The AO-177, first of a new class of Naval Auxiliary Oilers, experienced high levels of inboard airborne noise and initial-stage erosion damage on its skewed, seven-bladed propeller during builder's trails. This report describes the problems, corrective design modifications considered, and procedures and rationale used to develop a successful corrective design modification consisting of a fin to improve the flow into the propeller. To evaluate the problem, extensive model experiments were conducted, including flow visualization, wake survey, powering experiments, and a crucial series of cavitation experiments including propeller-induced hull pressure measurements in a large water tunnel. Experiments with two fin designs showed the superiority of a flow-accelerating configuration. Other experiments showed some benefits of altering the propeller blade shape. Propeller analyses were undertaken to provide design alternatives for retrofitting the ship with a new propeller. A full-scale trail with the final fin design provided evidence or reduction of the highest levels of airborne noise, reduction in the initial-stage erosion damage, and minimal effect on ship speed. The result is that the AO-177 has been accepted by the fleet for normal service. (Author)

Descriptors :   *Marine propellers, *Propeller noise, *Tanker ships, Noise reduction, Airborne, Skewness, Propeller blades, Erosion, Cavitation, Vibration, Damage, Hydrodynamic control surfaces, Fins, Water flow, Acceleration, Model tests, Water tunnels, Naval vessels, Auxiliary, Flow visualization

Subject Categories : Marine Engineering
      Acoustics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE