Download or read book Experimental Determination of Unsteady Forces on Contrarotating Propellers in Uniform Flow written by Marlin L. Miller and published by . This book was released on 1976 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Determination of Unsteady Forces on Contrarotating Propellers for Application to Torpedoes written by and published by . This book was released on 1981 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents results of measurements of unsteady forces and moments on 4x4 and 4x5 bladed sets of contrarotating propellers in uniform flow and in a 4-cycle wake for application to torpedo propeller design. The uniform flow measurements were made to check earlier results that had been in disagreement with the results from calculations based on propeller theory. The uniform flow results confirmed the earlier results in showing larger forces on the forward propeller which is contrary to the prediction of existing theory. The results of the experiments in the 4-cycle wake showed unsteady forces on the forward propeller due to the effect of the wake along with the interaction forces between the two propellers. No theoretical calculations are available for comparison with the wake results. The present procedure for conducting unsteady force and moment measurements on contrarotating propellers continues to be tedious and easily subject to error. Consequently, it is recommended that no further experiments be conducted using this procedure. It is recommended that for future experiments on contrarotating propellers the shafts be locked together mechanically and that a second dynamometer be used so that unsteady measurements can be made on both propellers simultaneously. (Author).

Download or read book Experimental Determination of Unsteady Forces on Contrarotating Propellers in Uniform Flow written by Marlin L. Miller and published by . This book was released on 1976 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NBS Special Publication written by and published by . This book was released on 1976 with total page 838 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unsteady Propeller Forces Fundamental Hydrodynamics and Unconventional Propulsion written by Ralph D. Cooper and published by . This book was released on 1971 with total page 1700 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydraulic Research in the United States and Canada 1974 written by Pauline H. Gurewitz and published by . This book was released on 1976 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hydraulic Research in the United States and Canada written by United States. National Bureau of Standards and published by . This book was released on 1978 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Propellers shafting 94 Symposium written by and published by . This book was released on 1994 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book MRIS Abstracts written by Maritime Research Information Service and published by . This book was released on 1977 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book SSC written by and published by . This book was released on 1946 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1982-04 with total page 890 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unsteady Propeller Loading Measurement Correlation With Theory and Parametric Study written by Robert J. Boswell and published by . This book was released on 1968 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Objectives of the present study are to measure the unsteady forces and moments on a series of marine propellers due to circumferentially nonuniform inflow; to correlate the measured unsteady thrust and torque with calculated values, based on various proposed theories; and to investigate variation of unsteady thrust and torque over a range of pertinent parameters, using the method determined from those described to be the best available for calculating unsteady loading. Experimental blade-frequency thrust and torque were compared with values calculated by the following techniques: quasi-steady, two-dimensional unsteady, combination quasi-steady two-dimensional unsteady, and three-dimensional unsteady. The three-dimensional unsteady theory yields the best correlation with experiment; however, the numerical techniques employed breakdown for narrow-bladed propellers and for propellers with blade overlap.

Download or read book Experimental Investigation of the Unsteady Forces Acting on a Reactangular Flat Plate Due to the Action of a Propeller written by August F. Lehman and published by . This book was released on 1968 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was undertaken in a water tunnel to determine the effect of propeller blade thickness, operating KT value, propeller tip-plate clearance and plate width on the forces, moments and pressure induced on a flat plate. The plate was oriented so as to be parallel with the rotational axis of the propeller. Propellers having three blades were tested, with one propeller design having blade thicknesses double that of the other but with both propellers having equal thrust - RPM performance. Plate widths were equal to 1 and 3 propeller radii, with the length of the plate constant at 6 propeller radii. The pressure was measured by a small flush mounted transducer located in the center of the plate surface and directly over the propeller. A comparison of certain theoretical predictions with the experimental force and pressure data resulted in generally good agreement. (Author).

Download or read book A Design Method and an Application for Contrarotating Propellers written by and published by . This book was released on 1990 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: A design methodology for contrarotating propellers has been developed based on rational hydromechanics. Three fundamental principles need to be satisfied: momentum, mass, and circulation conservation. Momentum conservation requires the net force generated by the contrarotating propeller to be balanced by the drag of the bare body and the drag due to hull-propulsor interaction. Mass conservation determines the circulation distribution of the aft propeller once the forward propeller circulation distribution is specified. Circulation conservation determines the magnitude of the circulation distribution of the aft propeller to ensure the proper thrust and torque ratios. The effects of the hub boundaries have been taken into account in the design and analysis methods. A contrarotating propeller set was designed for uniform flow at the operating point of the propeller for a high speed surface ship. Open water results show that the performance predictions agree well with the measurements. (KR).

Download or read book Measurement of Multiple Blade Rate Unsteady Propeller Forces written by Stuart D. Jessup and published by . This book was released on 1990 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of unsteady propeller forces was conducted using model propellers operating in idealized axial wakes. Three-bladed propellers were operated behind 3-, 6-, 9- and 12-cycle wake screens generating blade rate and multiple axial wake inflow harmonics. The axial wake distributions were measured using a Pitot tube. Unsteady propeller bearing thrust and torque were measured with an unsteady force dynamometer. Measurements were compared to calculations using unsteady propeller lifting surface theory. Also, Laser Doppler Velocimetry (LDV) was used to measure the unsteady flow field about the propeller. LDV measurements were used to evaluate the effect of the propeller on the incoming wake. Keywords: Marine propellers; Unsteady loads; Bearing forces; Model tests; Propeller blades. (edc).

Download or read book Oceanic Engineering International written by and published by . This book was released on 2002 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Optimization Method for the Reduction of Propeller Unsteady Forces written by Thomas S. Mauther and published by . This book was released on 1988 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the work of Greenblatt (1978), an enhanced optimization technique for the reduction of propeller unsteady forces and the determination of skew distributions has been developed. The current method provides an efficient propeller design tool capable of determining a variety of cubic or quadratic skew distributions, subject to constraints, which minimize the unsteady forces produced by the various harmonic components of the input wake. The original skew optimization method was extended to include higher order harmonics, and the original force calculation method was replaced by an extended version of the method developed by Thompson (1976). Calculation of forces and skew distributions associated with a representative propeller show that acceptable reduction of unsteady forces can be obtained without having to place severe restrictions on the model constraints. The problem considered herein is the generation of propeller noise due to non-uniform inflow velocity fields. This has been still is an issue of research in the area of marine propellers, and it is felt that a recently developed method of calculating unsteady forces may also be applicable in the design and analysis of aircraft propellers. Angle-of-attack fluctuations result in unsteady blade loadings and the generation of propeller noise, and the noise sources are characterized by three types of unsteady force mechanisms: a) turbulence injection; b) vortex shedding; and c) blade-rate.