Author: John J. Nelka
Publisher:
ISBN:
Category : Cavitation
Languages : en
Pages : 84
Book Description
Results are given showing the experimental effect of propeller-blade warp on open-water performance, cavitation performance, unsteady field-point pressures, and unsteady propeller loading for a series of warped propellers. Blade warp is defined as the angular displacement at the midchord point of the blade section from the blade reference line in the plane of rotation. Open-water results indicate that at the design thrust-loading coefficient and shaft horsepower the warped propellers are as much as 4.5 percent less than the design rpm. Cavitation results show a widening of the cavitation-free bucket with increasing warp; however, there is some crossover in the inception of back cavitation and tip-vortex cavitation. Field-point pressures and the unsteady propeller forces and moments have been found to decrease with increasing warp to reductions previously achieved with blade skew. (Author).
Experimental Evaluation of a Series of Skewed Propellers with Forward Rake
Author: John J. Nelka
Publisher:
ISBN:
Category : Cavitation
Languages : en
Pages : 84
Book Description
Results are given showing the experimental effect of propeller-blade warp on open-water performance, cavitation performance, unsteady field-point pressures, and unsteady propeller loading for a series of warped propellers. Blade warp is defined as the angular displacement at the midchord point of the blade section from the blade reference line in the plane of rotation. Open-water results indicate that at the design thrust-loading coefficient and shaft horsepower the warped propellers are as much as 4.5 percent less than the design rpm. Cavitation results show a widening of the cavitation-free bucket with increasing warp; however, there is some crossover in the inception of back cavitation and tip-vortex cavitation. Field-point pressures and the unsteady propeller forces and moments have been found to decrease with increasing warp to reductions previously achieved with blade skew. (Author).
Publisher:
ISBN:
Category : Cavitation
Languages : en
Pages : 84
Book Description
Results are given showing the experimental effect of propeller-blade warp on open-water performance, cavitation performance, unsteady field-point pressures, and unsteady propeller loading for a series of warped propellers. Blade warp is defined as the angular displacement at the midchord point of the blade section from the blade reference line in the plane of rotation. Open-water results indicate that at the design thrust-loading coefficient and shaft horsepower the warped propellers are as much as 4.5 percent less than the design rpm. Cavitation results show a widening of the cavitation-free bucket with increasing warp; however, there is some crossover in the inception of back cavitation and tip-vortex cavitation. Field-point pressures and the unsteady propeller forces and moments have been found to decrease with increasing warp to reductions previously achieved with blade skew. (Author).
Experimental Spindle Torque and Open-water Performance of Two Skewed Controllable-pitch Propellers
Author: Robert J. Boswell
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 196
Book Description
Experimental results are presented on the spindle torque and open-water performance of two skewed controllable-pitch propellers. Both propellers have radial distributions of skew specified so that the section midchord is forward of the spindle axis at the inner radii and aft of the spindle axis at the outer radii. One propeller has no rake and the other has substantial forward rake. The experiments were conducted at steady conditions in uniform flow in a towing basin over a range of positive and negative pitch ratios and a range of positive and negative advance coefficients so that the complete maneuvering envelope of the ship was simulated in a quasi-steady manner. The experimental open-water performance was correlated with calculated values based on a least-squares fit to previous systematic experimental data.
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 196
Book Description
Experimental results are presented on the spindle torque and open-water performance of two skewed controllable-pitch propellers. Both propellers have radial distributions of skew specified so that the section midchord is forward of the spindle axis at the inner radii and aft of the spindle axis at the outer radii. One propeller has no rake and the other has substantial forward rake. The experiments were conducted at steady conditions in uniform flow in a towing basin over a range of positive and negative pitch ratios and a range of positive and negative advance coefficients so that the complete maneuvering envelope of the ship was simulated in a quasi-steady manner. The experimental open-water performance was correlated with calculated values based on a least-squares fit to previous systematic experimental data.
NBS Special Publication
Author:
Publisher:
ISBN:
Category : Weights and measures
Languages : en
Pages : 838
Book Description
Publisher:
ISBN:
Category : Weights and measures
Languages : en
Pages : 838
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 970
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 970
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Hydraulic Research in the United States and Canada, 1974
Author: Pauline H. Gurewitz
Publisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages : 364
Book Description
Publisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages : 364
Book Description
Practical Methods for Predicting Periodic Propeller Loads
Author: Robert J. Boswell
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 52
Book Description
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 52
Book Description
Hydraulic Research in the United States and Canada
Author:
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 708
Book Description
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 708
Book Description
Static Stress Measurements on a Series of Skewed Propeller Blades with and Without Forward Rake
Author: Robert J. Boswell
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 82
Book Description
Static strains were measured in a systematic series of five marine propeller blades. The propeller blades have projected skew angle at the blade tip equal to zero, 36 degrees and 72 degrees without rake, and 36 and 72 degrees with sufficient forward rake to place the locus of the section midchord in the propeller plane. This combination of skew and rake is called warp. The primary experiments were conducted with the blades under uniform loading applied with air pressure using specially constructed chambers. Limited supplemental experiments were conducted using concentrated loads. The experimental results under uniform loading were correlated with modified beam theory. Both the experimental results and the modified beam theory indicate that for all the skewed and warped propeller blades evaluated, the largest value of the maximum principal stress is no greater than 1.20 times the maximum prinicipal stress on the unskewed propeller.
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 82
Book Description
Static strains were measured in a systematic series of five marine propeller blades. The propeller blades have projected skew angle at the blade tip equal to zero, 36 degrees and 72 degrees without rake, and 36 and 72 degrees with sufficient forward rake to place the locus of the section midchord in the propeller plane. This combination of skew and rake is called warp. The primary experiments were conducted with the blades under uniform loading applied with air pressure using specially constructed chambers. Limited supplemental experiments were conducted using concentrated loads. The experimental results under uniform loading were correlated with modified beam theory. Both the experimental results and the modified beam theory indicate that for all the skewed and warped propeller blades evaluated, the largest value of the maximum principal stress is no greater than 1.20 times the maximum prinicipal stress on the unskewed propeller.
Applied Mechanics Reviews
Author:
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 628
Book Description
Publisher:
ISBN:
Category : Mechanics, Applied
Languages : en
Pages : 628
Book Description
Propellers '81
Author:
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 532
Book Description
Publisher:
ISBN:
Category : Propellers
Languages : en
Pages : 532
Book Description