A propeller was designed and tested for the National Oceanic and Atmospheric Administration (NOAA) fisheries research vessel FRV-40. The ship is propelled by a single propeller operating in the wake of a skeg. The radiated noise goal required the propeller to be capable of operating cavitation free at a speed of at least 11 knots. The propeller was also required to meet ABS ice class C0. A five-bladed, fixed-pitch propeller was designed to meet the requirement. The design was completed using lifting line, lifting surface, and panel codes. The design propeller incorporates tip unloading, large diameter, thick blades, and long chord lengths to achieve the required performance. Open water and powering tests were performed at the David Taylor Model Basin. Cavitation evaluation testing was performed in the Navy's Large Cavitation Channel.
{"title":"Quiet Propeller Design for a Fisheries research Vessel","authors":"T. Michael, S. Jessup, M. Wilson","doi":"10.5957/pss-2000-13","DOIUrl":"https://doi.org/10.5957/pss-2000-13","url":null,"abstract":"A propeller was designed and tested for the National Oceanic and Atmospheric Administration (NOAA) fisheries research vessel FRV-40. The ship is propelled by a single propeller operating in the wake of a skeg. The radiated noise goal required the propeller to be capable of operating cavitation free at a speed of at least 11 knots. The propeller was also required to meet ABS ice class C0. A five-bladed, fixed-pitch propeller was designed to meet the requirement. The design was completed using lifting line, lifting surface, and panel codes. The design propeller incorporates tip unloading, large diameter, thick blades, and long chord lengths to achieve the required performance. Open water and powering tests were performed at the David Taylor Model Basin. Cavitation evaluation testing was performed in the Navy's Large Cavitation Channel.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132543533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The U.S. Coast Guard has traditionally used the methodology and criteria in MIL-STD-167-2A and its predecessors for acceptance testing of new ship propulsion systems. The original standard was written in 1954, with geared turbine drives in mind. It has been changed somewhat over the years but has not kept up with the development of new types of propulsion systems. The Coast Guard tasked John J. McMullen Associates, Inc. to propose a new standard with updated requirements for conventional propulsion systems, and to include requirements in the new standard for nonconventional propulsion systems such as thrusters, cycloidal propellers, and water-jets. For conventional systems, a review of existing criteria from the U.S. and other countries was performed. In the case of thrusters, water jets and cycloidal propellers, there are no U.S. or international standards covering these systems, so several manufacturers were requested to famish any relevant data and their recommendations. A draft of this standard was distributed widely to industry and government to get comments and suggestions. This report explains the rationale behind the proposed criteria.
美国海岸警卫队传统上使用MIL-STD-167-2A及其前身的方法和标准进行新船舶推进系统的验收测试。最初的标准是在1954年写的，考虑到齿轮涡轮机驱动。多年来，它已经发生了一些变化，但没有跟上新型推进系统的发展。海岸警卫队责成John J. McMullen Associates, Inc.提出一项新标准，更新传统推进系统的要求，并将非常规推进系统(如推进器、摆线螺旋桨和水射流)的要求纳入新标准。对于传统系统，对美国和其他国家的现有标准进行了审查。至于推进器、水射流和摆线螺旋桨，目前还没有涵盖这些系统的美国或国际标准，因此几家制造商被要求提供相关数据和他们的建议。该标准的草案已广泛分发给行业和政府，以征求意见和建议。本报告解释了拟议标准背后的理由。
{"title":"The Development of a New Standard for the Vibration of Ship Propulsion Systems","authors":"G. Antonides, S. Feldman","doi":"10.5957/pss-2000-19","DOIUrl":"https://doi.org/10.5957/pss-2000-19","url":null,"abstract":"The U.S. Coast Guard has traditionally used the methodology and criteria in MIL-STD-167-2A and its predecessors for acceptance testing of new ship propulsion systems. The original standard was written in 1954, with geared turbine drives in mind. It has been changed somewhat over the years but has not kept up with the development of new types of propulsion systems. The Coast Guard tasked John J. McMullen Associates, Inc. to propose a new standard with updated requirements for conventional propulsion systems, and to include requirements in the new standard for nonconventional propulsion systems such as thrusters, cycloidal propellers, and water-jets. For conventional systems, a review of existing criteria from the U.S. and other countries was performed. In the case of thrusters, water jets and cycloidal propellers, there are no U.S. or international standards covering these systems, so several manufacturers were requested to famish any relevant data and their recommendations. A draft of this standard was distributed widely to industry and government to get comments and suggestions. This report explains the rationale behind the proposed criteria.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131038472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Torsional vibration analysis is a cheap, fast and efficient tool when it comes to evaluating the performance and safety of a propulsion plant. The present paper introduces the basic mathematical concepts of three different approaches to torsional vibration analysis: natural frequency analysis, forced vibration analysis and transient analysis. The second half of the paper is dedicated to jive real life examples of the application of the three approaches. The examples cover natural frequencies and natural modes, single harmonic excitation, realistic harmonic excitation, the dynamics during run-up and finally the dynamics for a System equipped with a coupling with progressive stiffness.
{"title":"Torsional Vibration Analysis of Propulsion Plants","authors":"J. Nielsen, Herbert Roeser","doi":"10.5957/pss-2000-17","DOIUrl":"https://doi.org/10.5957/pss-2000-17","url":null,"abstract":"Torsional vibration analysis is a cheap, fast and efficient tool when it comes to evaluating the performance and safety of a propulsion plant. The present paper introduces the basic mathematical concepts of three different approaches to torsional vibration analysis: natural frequency analysis, forced vibration analysis and transient analysis. The second half of the paper is dedicated to jive real life examples of the application of the three approaches. The examples cover natural frequencies and natural modes, single harmonic excitation, realistic harmonic excitation, the dynamics during run-up and finally the dynamics for a System equipped with a coupling with progressive stiffness.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132556975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes the determination of the oscillatory loads generated by a propeller operating in an irregular wakefield. The vibrations caused by these loads can damage the shaft and its bearings or cause undesirable noise. The method used in this determination is the two-dimensional unsteady method based on Sears function. The loads are corrected for the aspect ratio of the propeller blades. The results are compared with results from literature. The influences of the skew angle and number of blades in the reduction of shaft vibrations are also evaluated, qualitatively and quantitatively, for a single propeller ship model.
{"title":"Estimate of the Propeller Oscillatory Loads Introduced in the Shaft and their Reduction Using Skew Angle","authors":"R. Sbragio","doi":"10.5957/pss-2000-15","DOIUrl":"https://doi.org/10.5957/pss-2000-15","url":null,"abstract":"This paper describes the determination of the oscillatory loads generated by a propeller operating in an irregular wakefield. The vibrations caused by these loads can damage the shaft and its bearings or cause undesirable noise. The method used in this determination is the two-dimensional unsteady method based on Sears function. The loads are corrected for the aspect ratio of the propeller blades. The results are compared with results from literature. The influences of the skew angle and number of blades in the reduction of shaft vibrations are also evaluated, qualitatively and quantitatively, for a single propeller ship model.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126071499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A fully three-dimensional unsteady Euler solver, based on a finite volume approach and the pressure-correction method, is developed and applied to the prediction of the effective wake for propellers subject to non-axisymmetric inflows. The method is coupled with an existing vortex lattice method for the analysis of unsteady cavitating propeller flows. The propeller is modeled as the unsteady force at the location of the blade and appears as the body force term in the Euler equations. The unsteady Euler solver is first validated against the solution obtained by a previously developed steady Euler solver for a non-axisymmetric inflow, and then against the solution by the potential flow solver in the uniform inflow case. The unsteady effective wake is predicted for a non-axisymmetric nominal wake, and it is found that the unsteadiness in the effective wake is small in this case. Lastly, the predicted total velocity field is compared with the experimental data obtained from the MIT water tunnel.
{"title":"Non-axisymmetric Effective Wake Prediction by Using an Unsteady Three-Dimensional Euler Solver","authors":"Jin-Keun Choi, S. Kinnas","doi":"10.5957/pss-2000-14","DOIUrl":"https://doi.org/10.5957/pss-2000-14","url":null,"abstract":"A fully three-dimensional unsteady Euler solver, based on a finite volume approach and the pressure-correction method, is developed and applied to the prediction of the effective wake for propellers subject to non-axisymmetric inflows. The method is coupled with an existing vortex lattice method for the analysis of unsteady cavitating propeller flows. The propeller is modeled as the unsteady force at the location of the blade and appears as the body force term in the Euler equations. The unsteady Euler solver is first validated against the solution obtained by a previously developed steady Euler solver for a non-axisymmetric inflow, and then against the solution by the potential flow solver in the uniform inflow case. The unsteady effective wake is predicted for a non-axisymmetric nominal wake, and it is found that the unsteadiness in the effective wake is small in this case. Lastly, the predicted total velocity field is compared with the experimental data obtained from the MIT water tunnel.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131325916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
At the end of the year 1999, the German shipyard HDW (Howaldtswerke Deutsche Werft) delivered a series of two open-top reefer container vessels of 2 million cu-ft each to the renowned fruit shipping company Dole Fresh Fruit. The vessels entered service at the end of 1999 and were then the largest of their kind. HSVA (the Hamburg Ship Model Basin) has conducted the model tests in advance. The propellers have been manufactured by the German company MMG (Mecklenburger MetallgujB). The article describes the propeller design specification (with special emphasis on low vibration levels in the accommodation areas), propeller design considerations, and test results (powering performance, cavitation performance, and vibration excitation) with three different model propellers. The authors also present the full-scale sea trial results as far as they are available.
1999年底，德国造船厂HDW (Howaldtswerke Deutsche Werft)向著名的水果运输公司Dole Fresh fruit交付了一系列两艘200万立方英尺的开放式冷藏集装箱船。这两艘船于1999年底投入使用，当时是同类船中最大的。HSVA(汉堡船舶模型盆地)已经提前进行了模型试验。螺旋桨已经由德国公司MMG (Mecklenburger MetallgujB)制造。本文介绍了三种不同型号螺旋桨的螺旋桨设计规范(特别强调调节区域的低振动水平)，螺旋桨设计考虑因素和测试结果(动力性能，空化性能和振动激励)。作者还提出了全面的海上试验结果，只要他们是可用的。
{"title":"The Development of the Propeller Design for the World's Largest Reefer Container Ships","authors":"K. Meyne, E. Praefke, K. Koop","doi":"10.5957/pss-2000-12","DOIUrl":"https://doi.org/10.5957/pss-2000-12","url":null,"abstract":"At the end of the year 1999, the German shipyard HDW (Howaldtswerke Deutsche Werft) delivered a series of two open-top reefer container vessels of 2 million cu-ft each to the renowned fruit shipping company Dole Fresh Fruit. The vessels entered service at the end of 1999 and were then the largest of their kind. HSVA (the Hamburg Ship Model Basin) has conducted the model tests in advance. The propellers have been manufactured by the German company MMG (Mecklenburger MetallgujB). The article describes the propeller design specification (with special emphasis on low vibration levels in the accommodation areas), propeller design considerations, and test results (powering performance, cavitation performance, and vibration excitation) with three different model propellers. The authors also present the full-scale sea trial results as far as they are available.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114933293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Achkinadze, Vladimir L. Krasihiikov, I. Stepanov
This paper presents the hydrodynamic design procedure for multi-stage blade-row marine propulsors using the original authors' model of the vortex wake. The special attention is paid to optimization algorithms that solve the problems about optimum spanwise circulation distribution and optimum chord length and thickness of the blade sections for wake-adapted propellers. A developed method allows the design of the podded propulsors and captures the potential part of the blade rows I pod "effective" velocity field. The contra-rotating propellers, rotor wane wheel device, and notional AZIPOD with tandem propellers are considered to illustrate the design procedure.
{"title":"A Hydrodynamic Design Procedure for Multi-Stage Blade-Row Propulsors Using Generalized Linear Model of the Vortex Wake","authors":"A. Achkinadze, Vladimir L. Krasihiikov, I. Stepanov","doi":"10.5957/pss-2000-20","DOIUrl":"https://doi.org/10.5957/pss-2000-20","url":null,"abstract":"This paper presents the hydrodynamic design procedure for multi-stage blade-row marine propulsors using the original authors' model of the vortex wake. The special attention is paid to optimization algorithms that solve the problems about optimum spanwise circulation distribution and optimum chord length and thickness of the blade sections for wake-adapted propellers. A developed method allows the design of the podded propulsors and captures the potential part of the blade rows I pod \"effective\" velocity field. The contra-rotating propellers, rotor wane wheel device, and notional AZIPOD with tandem propellers are considered to illustrate the design procedure.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130083060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Since the introduction of the keyless hydraulic coupling in the early 40's. many new applications have been developed and benefits realized. One of the latest applications is using the couplings together with GARB rolling bearings on straight shafts in a modular design for shafting arrangements. This has been made possible by combining their unique benefits: both are mounted easily on cylindrical shafts by oil-injection and the GARB bearing has, through its design, a self-aligning adjustment and a wide axial float. These features provide for a shafting arrangement that can be made in ready-to-install, modules that require no extra machining at installation. As the system is modular, and parts in many cases identical, the need for spares will be highly reduced An additional benefit, that in some applications may be a major one, is the reduced friction compared with normal journal bearings. A reduction that In the long run gives both fuel savings and can reduce the required engine size: The oil-injection method (OIM) and keyless hydraulic couplings can also be found in a number of other shafting applications as their use has expanded over the years. Some of the applications are gear & flex couplings mounted with a sleeve and OIM design, propeller sleeves, double sleeves, etc. All of them having one thing in common: A quick and easy installation and removal process.
{"title":"Modular Design of Shafting Arrangement with Hydraulic Couplings and CARB Rolling Bearings","authors":"Stefan Norberg","doi":"10.5957/pss-2000-21","DOIUrl":"https://doi.org/10.5957/pss-2000-21","url":null,"abstract":"Since the introduction of the keyless hydraulic coupling in the early 40's. many new applications have been developed and benefits realized.\u0000 One of the latest applications is using the couplings together with GARB rolling bearings on straight shafts in a modular design for shafting arrangements. This has been made possible by combining their unique benefits: both are mounted easily on cylindrical shafts by oil-injection and the GARB bearing has, through its design, a self-aligning adjustment and a wide axial float.\u0000 These features provide for a shafting arrangement that can be made in ready-to-install, modules that require no extra machining at installation. As the system is modular, and parts in many cases identical, the need for spares will be highly reduced An additional benefit, that in some applications may be a major one, is the reduced friction compared with normal journal bearings. A reduction that In the long run gives both fuel savings and can reduce the required engine size:\u0000 The oil-injection method (OIM) and keyless hydraulic couplings can also be found in a number of other shafting applications as their use has expanded over the years. Some of the applications are gear & flex couplings mounted with a sleeve and OIM design, propeller sleeves, double sleeves, etc. All of them having one thing in common: A quick and easy installation and removal process.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126267075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A technique for the analysis of propulsor-induced maneuvering forces on the surface and underwater vehicles has been developed. The method is capable of modeling general propulsors but is especially suited to complex integrated propulsors and their highly contracting stern flows. Integrated propulsors exhibit strong interactions of the blade-rows, duct, and vehicle stern. The method described herein is a robust means to analyze propulsor-induced maneuvering forces, including those arising from complex propulsors. The heart of the maneuvering force prediction is a three-dimensional, unsteady lifting surface method for the calculation of blade forces on both rotors and stators. The lifting surface method includes features that are important for the modeling of complex propulsors. Temporally-varying forces are computed for a blade-row rotating in a spatially-varying flow field. The spatially-varying flowfield around a maneuvering vehicle is obtained by coupling the unsteady lifting-surface method with a three-dimensional, time-averaged Reynolds Averaged Navier-Stokes viscous flow solver. The coupled technique allows the designer to compute maneuvering forces while accounting for effective wake issues and propulsor-hull interactions. Issues important to the coupling of a potential-flow method and a three-dimensional viscous flow solver are discussed. Verification of the method has been performed on a variety of geometries and vehicles. Two examples are shown. Preliminary results show that the method is able to compute propulsor-induced maneuvering forces for such vehicles. The results suggest that this maneuvering force prediction method has great potential for the propulsor designer.
{"title":"A Coupled Viscous/Potential-Flow Method for the Prediction of Propulsor-Induced Maneuvering Forces","authors":"C. L. Warren, T. E. Taylor, J. Kerwin","doi":"10.5957/pss-2000-18","DOIUrl":"https://doi.org/10.5957/pss-2000-18","url":null,"abstract":"A technique for the analysis of propulsor-induced maneuvering forces on the surface and underwater vehicles has been developed. The method is capable of modeling general propulsors but is especially suited to complex integrated propulsors and their highly contracting stern flows. Integrated propulsors exhibit strong interactions of the blade-rows, duct, and vehicle stern. The method described herein is a robust means to analyze propulsor-induced maneuvering forces, including those arising from complex propulsors.\u0000 The heart of the maneuvering force prediction is a three-dimensional, unsteady lifting surface method for the calculation of blade forces on both rotors and stators. The lifting surface method includes features that are important for the modeling of complex propulsors.\u0000 Temporally-varying forces are computed for a blade-row rotating in a spatially-varying flow field. The spatially-varying flowfield around a maneuvering vehicle is obtained by coupling the unsteady lifting-surface method with a three-dimensional, time-averaged Reynolds Averaged Navier-Stokes viscous flow solver. The coupled technique allows the designer to compute maneuvering forces while accounting for effective wake issues and propulsor-hull interactions. Issues important to the coupling of a potential-flow method and a three-dimensional viscous flow solver are discussed.\u0000 Verification of the method has been performed on a variety of geometries and vehicles. Two examples are shown. Preliminary results show that the method is able to compute propulsor-induced maneuvering forces for such vehicles. The results suggest that this maneuvering force prediction method has great potential for the propulsor designer.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133823393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. F. McMahon, C. Dai, S. Gowing, G. Lin, F. P. Peterson
A ventilated waterjet (VW) is similar to a conventional waterjet with a fully submerged inlet region. However, the exit of a VW is partially submerged and the impeller blade is designed for ventilating conditions. The partially submerged exit provides a natural supply of air for ventilating the blade surfaces under most operating conditions. A VW can be used for high-speed vessels where traditional propulsors fail to perform due to cavitation limitations. It also can address some of the shortcomings typical of super cavitating or partially submerged propellers. The 24" water tunnel at the David Taylor Model Basin was modified to accommodate the testing of a VW. A stock surface piercing propeller with trimmed blade tips was tested in the ventilating mode and the results compared with a modified version of a Propeller Unsteady Force computer program. The general operating characteristics of a VW were identified in the 24" water tunnel tests. The results indicate that a VW could have better-powering performance over a wider speed range as compared with either super cavitating or surface-piercing propellers.
{"title":"Ventilated Waterjets for High Speed Ships","authors":"J. F. McMahon, C. Dai, S. Gowing, G. Lin, F. P. Peterson","doi":"10.5957/pss-2000-11","DOIUrl":"https://doi.org/10.5957/pss-2000-11","url":null,"abstract":"A ventilated waterjet (VW) is similar to a conventional waterjet with a fully submerged inlet region. However, the exit of a VW is partially submerged and the impeller blade is designed for ventilating conditions. The partially submerged exit provides a natural supply of air for ventilating the blade surfaces under most operating conditions. A VW can be used for high-speed vessels where traditional propulsors fail to perform due to cavitation limitations. It also can address some of the shortcomings typical of super cavitating or partially submerged propellers. The 24\" water tunnel at the David Taylor Model Basin was modified to accommodate the testing of a VW. A stock surface piercing propeller with trimmed blade tips was tested in the ventilating mode and the results compared with a modified version of a Propeller Unsteady Force computer program. The general operating characteristics of a VW were identified in the 24\" water tunnel tests. The results indicate that a VW could have better-powering performance over a wider speed range as compared with either super cavitating or surface-piercing propellers.","PeriodicalId":295991,"journal":{"name":"Day 2 Thu, September 21, 2000","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2000-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125914238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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