Accession Number : ADA300858

Title :   Development of Experimental Inversion and Simulation Techniques to Study Propeller Blade Response to Inflow Distortion.

Descriptive Note : Final rept. 1 Oct 92-31 Dec 94,

Corporate Author : NOTRE DAME UNIV IN DEPT OF AEROSPACE AND MECHANICAL ENGINEERING

Personal Author(s) : Mueller, T. J. ; Scharpf, D. F. ; Subramanian, S. ; Sullivan, C. J. ; Minniti, R. J., III

PDF Url : ADA300858

Report Date : FEB 1995

Pagination or Media Count : 109

Abstract : Marine propellers usually operate either in the non-uniform wake of a submarine or skewed flow under the stern of a surface ship. Therefore, the flow upstream of marine propeller blades is characterized by irregular patterns which are caused by various mean flow distortions due to the boundary layer growth on the hull of the ship, turbulent viscous wakes of upstream bodies (e.g., Hyun and Patel (1991)) or obstacles (e.g., Groves et al (1992)). Whether the inflow to the propeller is steady or unsteady, uniform or non-uniform, the flow over and downstream of the blades is unsteady. This unsteadiness can be due to a separation bubble near the leading edge of the blade, separated flow from the blade before the trailing edge, as well as tip and hub vortices. The unsteady flow over the blades produces unsteady hydrodynamic forces (i.e., excitations) which result in unwanted vibrations and noise. Inflow nonuniformities give rise to tonal and narrow band noise centered around the blade passing harmonics. Additional broad band signatures are superimposed due to turbulence-trailing edge interaction. Highly non-uniform and asymmetric inflows further exaggerate these effects. (MM)

Descriptors :   *WAKE, *MARINE PROPELLERS, *PROPELLER BLADES, *HYDRODYNAMIC CONTROL SURFACES, SIMULATION, VIBRATION, SHIPS, OCEAN SURFACE, PRESSURE TRANSDUCERS, TURBULENCE, TURBULENT FLOW, TURBULENT BOUNDARY LAYER, VORTICES, FLOW VISUALIZATION, FLOW FIELDS, BUBBLES, BROADBAND, LEADING EDGES, UNSTEADY FLOW, LIFT, SKEWNESS, VISCOSITY, SUBMARINES, FLOW SEPARATION, MICROPHONES, SOUND PRESSURE, GUST LOADS, RADIATED NOISE, BOUNDARY LAYER FLOW, PIEZOELECTRIC TRANSDUCERS, PIEZOELECTRIC GAGES.

Subject Categories : Marine Engineering
      Submarine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE