THEORETICAL AND EXPERIMENTAL TECHNIQUES FOR PRACTICAL ESTIMATION OF PROPELLER-INDUCED VIBRATORY FORCES
This paper is directed to naval architects and engineers having an interest in design of ships with minimum excitations from the propeller. The flow phenomenon involved in the generation of vibratory forces and couples is described in general, non-mathematical terms using, at first, the knowledge compiled from the study of wing sections and wings of finite span as they move through regular transverse gusts. The difference between quasisteady estimates and those involving unsteadiness is stressed as well as the influence of aspect ratio on both. The hull wake or inflow to a ship propeller is described in terms of its variation with blade position angle, these variations being defined by Fourier series. Results of calculations for propellers made on assumptions analogous to those for wings are exhibited together with experimentally determined values. Recent application of unsteady lifting surface theory to propeller blade stresses are also described and compared to measurements made at sea. An experimental procedure developed by Professor Emeritus F.M. Lewis at MIT is outlined and principal results displayed. A method is indicated by which results from both experiments and calculations may be compactly summarized for use as design charts. It is urged that application of unsteady lifting surface methods for propeller forces and the model experimental method for the net forces be applied to a sufficiently broad set of configurations to allow the construction of design charts from which ships of the future having minimal propeller excitations could be confidently designed.
- Presented at New York Met. Section of SNAME, Symposium on Ship Vibration, Feb 1970.
Society of Naval Architects and Marine Engineers601 Pavonia Avenue
Jersey City, NJ United States 07306-2907
- Breslin, J P
- Publication Date: 1970-2
- TRT Terms: Aerodynamic lift; Excitation; Hulls; Propeller shafts; Propellers; Vibration; Wakes
- Old TRIS Terms: Hull propeller interaction; Lifting surface theory; Propeller excitation; Propeller shaft vibration; Wake analysis
- Subject Areas: Marine Transportation; Vehicles and Equipment;
- Accession Number: 00019638
- Record Type: Publication
- Source Agency: Society of Naval Architects and Marine Engineers
- Files: TRIS
- Created Date: Nov 25 1971 12:00AM