Several experiments performed by Ceccio and Brennen ( 1991, 1989) and Kumar and Brennen 1992, 1991) have closely examined the interaction between individual cavitation bubbles and the boundary layer, as well as statistical properties of the acoustical signals produced by the bubble collapse. All of these experiments were, however, conducted in the same facility with the same head form size (5.08cm in diameter) and over a fairly narrow range of flow velocities (around 9m/s). Clearly this raises the issue of how the phenomena identified change with speed, scale and facility. The present paper describes experiments conducted in order to try to answer some of these important questions regarding the scaling of the cavitation phenomena. The experiments were conducted in the Large Cavitation Channel of the David Taylor Research Center in Memphis Tennessee, on geometrically similar Schiebe head forms which are 5. 0 8, 25.4 and 50.8cm in diameter for speeds ranging up to 15m/s and for a range of cavitation numbers.
{"title":"Cavitation Scaling Experiments with Axisymmetric Bodies","authors":"Y. Chizelle, S. Ceccio, C. Brennen, Young T. Shen","doi":"10.5957/attc-1992-021","DOIUrl":"https://doi.org/10.5957/attc-1992-021","url":null,"abstract":"Several experiments performed by Ceccio and Brennen ( 1991, 1989) and Kumar and Brennen 1992, 1991) have closely examined the interaction between individual cavitation bubbles and the boundary layer, as well as statistical properties of the acoustical signals produced by the bubble collapse. All of these experiments were, however, conducted in the same facility with the same head form size (5.08cm in diameter) and over a fairly narrow range of flow velocities (around 9m/s). Clearly this raises the issue of how the phenomena identified change with speed, scale and facility. The present paper describes experiments conducted in order to try to answer some of these important questions regarding the scaling of the cavitation phenomena. The experiments were conducted in the Large Cavitation Channel of the David Taylor Research Center in Memphis Tennessee, on geometrically similar Schiebe head forms which are 5. 0 8, 25.4 and 50.8cm in diameter for speeds ranging up to 15m/s and for a range of cavitation numbers.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"253 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116394133","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 inception cavitation number a 1 and corresponding propeller revolutions RPM are essential parameters for the prediction of the propeller noise. While RPM and a depend on many factors, the thrust loading coefficient Te and pitch ratio P/0 are important. In this contribution a simple expression, which comes from classical Burrill ship trial cavitation chart and modern model noise experimental analysis is presented. Based on the expression the predicted results for the noise spectra (SPL, vs. 1/3 octave frequency) are acceptable.
{"title":"An Expression of Inception Cavitation Number","authors":"S. Qin","doi":"10.5957/attc-1992-020","DOIUrl":"https://doi.org/10.5957/attc-1992-020","url":null,"abstract":"The inception cavitation number a 1 and corresponding propeller revolutions RPM are essential parameters for the prediction of the propeller noise. While RPM and a depend on many factors, the thrust loading coefficient Te and pitch ratio P/0 are important. In this contribution a simple expression, which comes from classical Burrill ship trial cavitation chart and modern model noise experimental analysis is presented. Based on the expression the predicted results for the noise spectra (SPL, vs. 1/3 octave frequency) are acceptable.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131185320","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}
Wake flow measurements have traditionally been made with pitot probes. Most commonly used probes are of the 5-hole spherical and hemispherical head on cylindrical stem variety. A limitation is that the measurement can be intrusive and the probe may not physically fit in the area to be measured. One modern solution uses multi-component Laser Doppler Velocimetry (LDV) to measure the wake profile. A question arises as to how the laser measurements comp are with the pitot probe measurements. Experimental studies were conducted at the David Taylor Model Basin, Carderock Division, Naval Surface Warfare Center (formerly the David Taylor Research Center) where pitot probe s and LDV measurements were simultaneously collected in the propeller plane of a single screw ship model. No n-simultaneous wake measurements have also been collected on twin screw shaft and strut ship models. The two flow measurements correlate well at the outer propeller radii. Near the hub or in low-flow regions, the pitot probe axial velocities fall off more rapidly than LDV measurements.
{"title":"Comparison of Wake Flow Measurements between 5-Hole Pitot Probes and Laser Doppler Velocimetry in the Ship Propeller Plane","authors":"M. Pirrone, W. Lindenmuth","doi":"10.5957/attc-1992-013","DOIUrl":"https://doi.org/10.5957/attc-1992-013","url":null,"abstract":"Wake flow measurements have traditionally been made with pitot probes. Most commonly used probes are of the 5-hole spherical and hemispherical head on cylindrical stem variety. A limitation is that the measurement can be intrusive and the probe may not physically fit in the area to be measured. One modern solution uses multi-component Laser Doppler Velocimetry (LDV) to measure the wake profile. A question arises as to how the laser measurements comp are with the pitot probe measurements.\u0000 Experimental studies were conducted at the David Taylor Model Basin, Carderock Division, Naval Surface Warfare Center (formerly the David Taylor Research Center) where pitot probe s and LDV measurements were simultaneously collected in the propeller plane of a single screw ship model. No n-simultaneous wake measurements have also been collected on twin screw shaft and strut ship models.\u0000 The two flow measurements correlate well at the outer propeller radii. Near the hub or in low-flow regions, the pitot probe axial velocities fall off more rapidly than LDV measurements.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131894032","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 explains the capabilities of a new right angle drive propeller dynamometry system which has recently been put into service at the Carderock Division of the Naval Surface Warfare Center (CDNSWC). The towing carriage mounted Fully Submerged Propulsor Dynamometer (FSPD) was designed to make precision steady state measurements of propeller thrust and torque while moving through the water at high speeds in the towing basin. Experiments may be performed at various depths and shaft inclination angles. The capabilities introduced by this new instrument will make investigations into many phenomena and the measurement of their effects on propeller performance possible. The FSPD has been used for obtaining the high speed open water performance for the large diameter propulsors used in cavitation experiments at CDNSWC. Experiments have been performed to determine the effects of the variation of propeller depth of submergence and Reynolds Numbers on open water performance. Some preliminary experimental results are presented in this paper.
{"title":"A Precision, High Capacity, High Speed, Right Angle Drive Fully Submerged Propulsor Dynamometry System (FSPD)","authors":"J. Anderson, A. Hampton","doi":"10.5957/attc-1992-037","DOIUrl":"https://doi.org/10.5957/attc-1992-037","url":null,"abstract":"This paper explains the capabilities of a new right angle drive propeller dynamometry system which has recently been put into service at the Carderock Division of the Naval Surface Warfare Center (CDNSWC). The towing carriage mounted Fully Submerged Propulsor Dynamometer (FSPD) was designed to make precision steady state measurements of propeller thrust and torque while moving through the water at high speeds in the towing basin. Experiments may be performed at various depths and shaft inclination angles. The capabilities introduced by this new instrument will make investigations into many phenomena and the measurement of their effects on propeller performance possible.\u0000 The FSPD has been used for obtaining the high speed open water performance for the large diameter propulsors used in cavitation experiments at CDNSWC. Experiments have been performed to determine the effects of the variation of propeller depth of submergence and Reynolds Numbers on open water performance. Some preliminary experimental results are presented in this paper.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116132802","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 presents the application of the Latorre-Ryan spray scaling relationship to the Geosim tests of eleven semi-planing hulls tested at Froude Number F = 1.0. Using the results of the spray scaling, it is possible to collapse the spray measurements into a single curve.
{"title":"Scaling of Main Spray Generated by Planing Surfaces","authors":"S. Ryan, R. Latorre","doi":"10.5957/attc-1992-041","DOIUrl":"https://doi.org/10.5957/attc-1992-041","url":null,"abstract":"This paper presents the application of the Latorre-Ryan spray scaling relationship to the Geosim tests of eleven semi-planing hulls tested at Froude Number F = 1.0. Using the results of the spray scaling, it is possible to collapse the spray measurements into a single curve.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122641533","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 Partnership for America's Cup Technology provided a 1:5 scale model of an International America's Cup Class yacht model and keel, which was tested at two drafts, both having the same radius of gyration and VCG. Test were made of upright resistance and model motions in smooth water and in regular waves. The model was free to surge, pitch, and heave while restraining all other degrees of freedom. Initial tests were made to compare the model in the free to surge mode (which is more realistic) and in the fixed in surge mode (which allows the determination of phase angles).
{"title":"Initial Seakeeping Tests on an IACC Yacht Hull Model: Two Ballast Conditions","authors":"S. Cohen, R. Beck","doi":"10.5957/attc-1992-007","DOIUrl":"https://doi.org/10.5957/attc-1992-007","url":null,"abstract":"The Partnership for America's Cup Technology provided a 1:5 scale model of an International America's Cup Class yacht model and keel, which was tested at two drafts, both having the same radius of gyration and VCG. Test were made of upright resistance and model motions in smooth water and in regular waves. The model was free to surge, pitch, and heave while restraining all other degrees of freedom. Initial tests were made to compare the model in the free to surge mode (which is more realistic) and in the fixed in surge mode (which allows the determination of phase angles).","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123558543","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 propeller design procedure incorporating new propeller blade sections has been developed to improve propeller cavitation inception. Two dimensional foil design procedures of Shen and Eppler provide geometry for a specified blade pressure distribution. Advanced propeller lifting surface design procedures then generate propeller geometry. Panel method analysis verifies final design changes. Resulting propeller geometries produce a specified blade pressure distribution with improved blade surface cavitation inception. A series of new blade section model propeller s has been designed and tested for cavitation and powering performance. The new propellers show a 2-3 knot improvement in blade surface cavitation inception speed. The new section propeller s also show some Reynolds number effects on powering, requiring higher speed testing than conventional blade section propellers.
{"title":"Improvement of Surface Ship Propeller Cavitation Performance Using Advanced Blade Sections","authors":"J. W. Bailar, S. Jessup, Y. Shen","doi":"10.5957/attc-1992-018","DOIUrl":"https://doi.org/10.5957/attc-1992-018","url":null,"abstract":"A propeller design procedure incorporating new propeller blade sections has been developed to improve propeller cavitation inception. Two dimensional foil design procedures of Shen and Eppler provide geometry for a specified blade pressure distribution. Advanced propeller lifting surface design procedures then generate propeller geometry. Panel method analysis verifies final design changes. Resulting propeller geometries produce a specified blade pressure distribution with improved blade surface cavitation inception.\u0000 A series of new blade section model propeller s has been designed and tested for cavitation and powering performance. The new propellers show a 2-3 knot improvement in blade surface cavitation inception speed. The new section propeller s also show some Reynolds number effects on powering, requiring higher speed testing than conventional blade section propellers.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128279152","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}
There has been renewed interest concerning the subject of scaling, to fullscale, the seakeeping motions of SES models. This paper has been prepared in response to this interest. The paper reviews the historical background to the subject as treated in the United States and the United Kingdom and important items of difficulty are discussed. Future studies which can further our understanding of the problem are suggested.
{"title":"Scaling SES [Surface Effect Ship] Motions","authors":"D. Lavis","doi":"10.5957/attc-1992-043","DOIUrl":"https://doi.org/10.5957/attc-1992-043","url":null,"abstract":"There has been renewed interest concerning the subject of scaling, to fullscale, the seakeeping motions of SES models. This paper has been prepared in response to this interest. The paper reviews the historical background to the subject as treated in the United States and the United Kingdom and important items of difficulty are discussed. Future studies which can further our understanding of the problem are suggested.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131214752","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}
Resistance model test results for a systematic series of low LIB, heavy displacement vessels are presented. The UBC Series is based on west coast seiners and trawlers. These vessels have low LIB and L/V/1/3 values that are outside the range of existing model series data. A parent hull form was developed that has 14% less resistance and yet has the same displacement as a typical fishing vessel. A series of 13 models was generated by systematically varying L/B, BIT and Cb. Results from resistance tests in calm water are presented. From these model tests, an algorithm has been developed to predict the resistance of similar small vessels. The implementation of bulbous bows to the parent hull shows reduction in the overall resistance by approximately 17%. Also, the introduction of stern fairing reduces the resistance by about 25% at the design speed.
{"title":"Resistance Tests with UBC Series Fishing Vessels","authors":"S. Calisal, J. Mikkelsen, D. Mcgreer","doi":"10.5957/attc-1992-012","DOIUrl":"https://doi.org/10.5957/attc-1992-012","url":null,"abstract":"Resistance model test results for a systematic series of low LIB, heavy displacement vessels are presented. The UBC Series is based on west coast seiners and trawlers. These vessels have low LIB and L/V/1/3 values that are outside the range of existing model series data. A parent hull form was developed that has 14% less resistance and yet has the same displacement as a typical fishing vessel. A series of 13 models was generated by systematically varying L/B, BIT and Cb. Results from resistance tests in calm water are presented. From these model tests, an algorithm has been developed to predict the resistance of similar small vessels. The implementation of bulbous bows to the parent hull shows reduction in the overall resistance by approximately 17%. Also, the introduction of stern fairing reduces the resistance by about 25% at the design speed.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127822032","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 small new facility has been installed in the Department of Naval Architecture of the University of Sao Paulo, Brazil. It is a wave flume, 14 meters long, 1 meter wide and 1 meter deep. Regular and irregular waves, as well as packages of waves, can be generated in the range 0.5 - 2.5 Hz, 0.5 - 5.0 cm. The wave generator is plunger-type, driven by a servo-motor. 2D tests with one and two cylinders have been conducted, varying the immersion and the distance between the cylinders. Forces acting on the cylinders, wave elevation and plunger motion have been measured. The paper describes the facility and presents the results for the stationary cylinders acted transversely by waves.
{"title":"2D Tests with One and Two Cylinders in Waves","authors":"M. de Conti","doi":"10.5957/attc-1992-036","DOIUrl":"https://doi.org/10.5957/attc-1992-036","url":null,"abstract":"A small new facility has been installed in the Department of Naval Architecture of the University of Sao Paulo, Brazil. It is a wave flume, 14 meters long, 1 meter wide and 1 meter deep. Regular and irregular waves, as well as packages of waves, can be generated in the range 0.5 - 2.5 Hz, 0.5 - 5.0 cm. The wave generator is plunger-type, driven by a servo-motor. 2D tests with one and two cylinders have been conducted, varying the immersion and the distance between the cylinders. Forces acting on the cylinders, wave elevation and plunger motion have been measured. The paper describes the facility and presents the results for the stationary cylinders acted transversely by waves.","PeriodicalId":211134,"journal":{"name":"Day 1 Thu, June 11, 1992","volume":"31 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123921172","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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