INDUCED FIELD-POINT PRESSURES OF A DUCTED PROPELLER SYSTEM
Total fluctuating pressures were measured on the internal surface of a 0-degree angle-of-attack duct of a ducted propeller system (Kort nozzle type). The effects of blade loading in uniform flow and propeller blade cavitation in nonuniform flow on the harmonics of the blade-frequency propeller-induced pressure were determined. Also determined were the blade-frequency pressure-induced duct forces. Experimental results indicate that the blade-frequency pressures increase for an increase in blade loading with the second and third blade-frequency pressure being significant with respect to the blade-frequency pressure. Fluctuating blade-frequency vertical forces determined by integrating the pressure results from nonuniform inflow noncavitating conditions were approximately 1-percent of the mean thrust. In the experiments conducted at a given loading, cavitation on the propeller blades tended to increase the blade-frequency pressure downstream of the propeller by as much as a factor of three.
Naval Ship Research and Development CenterAdvanced Ship Division
Bethesda, MD USA 20034
- Publication Date: 1974-10
- Pagination: 44 p.
- TRT Terms: Atmospheric pressure; Blade loading; Blades (Machinery); Ducted propellers; Vibration
- Old TRIS Terms: Blade frequency vibration; Pressure fluctuations
- Subject Areas: Marine Transportation; Vehicles and Equipment;
- Accession Number: 00084830
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: NSRDC-4270 Final Rpt.
- Files: TRIS
- Created Date: May 19 1975 12:00AM