Cavitation tunnels have played a critical role in the development of ships and other naval vehicles and the associated research applicable to the engineering of these vehicles. Particularly important has been the use of cavitation tunnels in the development of propulsion systems. The paper reviews some aspects of the historical development of the modern cavitation tunnel. It includes aspects of tunnel design such as size, speed, pressure range, acoustics, and materials. Model construction, installation, and instrumentation are discussed. Initially, the most innovative development occurred in 1895 with the invention of the cavitation tunnel by Sir Charles Parsons. More than 100 years later, the cavitation tunnel is still the key test facility used for cavitation research, test and evaluation. Technologies currently used for performance evaluation have changed greatly over those used only a decade or two ago. This has been in part due to incredible innovations in the area of instrumentation and digital electronics as well as the need to characterize modern propulsors in ways not previously required. The evolution of cavitation tunnel capabilities and the use of the tunnel in a large marine research, development, and design organization is largely reviewed by considering the various cavitation tunnels which have been constructed and utilized at the David Taylor Model Basin over several decades.
{"title":"State of the Art - Cavitation Test Facilities and Experimental Methods","authors":"R. Etter","doi":"10.5957/attc-2001-016","DOIUrl":"https://doi.org/10.5957/attc-2001-016","url":null,"abstract":"Cavitation tunnels have played a critical role in the development of ships and other naval vehicles and the associated research applicable to the engineering of these vehicles. Particularly important has been the use of cavitation tunnels in the development of propulsion systems. The paper reviews some aspects of the historical development of the modern cavitation tunnel. It includes aspects of tunnel design such as size, speed, pressure range, acoustics, and materials. Model construction, installation, and instrumentation are discussed. Initially, the most innovative development occurred in 1895 with the invention of the cavitation tunnel by Sir Charles Parsons. More than 100 years later, the cavitation tunnel is still the key test facility used for cavitation research, test and evaluation. Technologies currently used for performance evaluation have changed greatly over those used only a decade or two ago. This has been in part due to incredible innovations in the area of instrumentation and digital electronics as well as the need to characterize modern propulsors in ways not previously required. The evolution of cavitation tunnel capabilities and the use of the tunnel in a large marine research, development, and design organization is largely reviewed by considering the various cavitation tunnels which have been constructed and utilized at the David Taylor Model Basin over several decades.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"186 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131503704","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 propulsion factor called thrust-deduction fraction, t, trets the interaction of the propeller with the hull when the ship is underway and is an important element in determining the propulsive performance of a vessel. The reduced pressure field created by the propeller at the stern of a ship effectively increases the ship's resistance. The naval architect treats this increase in resistance as a deduction from the propeller thrust.
{"title":"The Effect of Propeller Loading on Thrust Deduction","authors":"J. Hadler","doi":"10.5957/attc-2001-009","DOIUrl":"https://doi.org/10.5957/attc-2001-009","url":null,"abstract":"The propulsion factor called thrust-deduction fraction, t, trets the interaction of the propeller with the hull when the ship is underway and is an important element in determining the propulsive performance of a vessel. The reduced pressure field created by the propeller at the stern of a ship effectively increases the ship's resistance. The naval architect treats this increase in resistance as a deduction from the propeller thrust.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129682235","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}
Webb Institute is.one of the few remaining institutions in the United States, devoted to educating students in Naval Architecture and Marine Engineering at the undergraduate level. Within the context of its educational program, a towing tank was constructed to be able to give hands-on experience to its students in the area of resistance and, later, seakeeping experiments. The facility was named the Robinson Model Basin (RMB) in honor of Admiral Robinson, Webb's president from 1945 to 1950. The primary purpose of the towing tank was always to serve the educational program, although some research and development work was, of course, performed by the Webb faculty. It suffices to mention the work on wave resistance by Ward, the trawler series by Nevitt, the springing research by Hoffman and Van Hooff, among others. What we wish to address now is the towing tank as it relates to: modem trends in the maritime business and in naval architecture education. The primary purpose of this contribution is to solicit the comments of attendees of the 26 ATTC on our conclusions. We welcome your suggestions.
{"title":"The Future of Webb's Towing Tank","authors":"R. W. Van Hooff, N. Gallagher, R. H. Compton","doi":"10.5957/attc-2001-018","DOIUrl":"https://doi.org/10.5957/attc-2001-018","url":null,"abstract":"Webb Institute is.one of the few remaining institutions in the United States, devoted to educating students in Naval Architecture and Marine Engineering at the undergraduate level. Within the context of its educational program, a towing tank was constructed to be able to give hands-on experience to its students in the area of resistance and, later, seakeeping experiments. The facility was named the Robinson Model Basin (RMB) in honor of Admiral Robinson, Webb's president from 1945 to 1950. The primary purpose of the towing tank was always to serve the educational program, although some research and development work was, of course, performed by the Webb faculty. It suffices to mention the work on wave resistance by Ward, the trawler series by Nevitt, the springing research by Hoffman and Van Hooff, among others. What we wish to address now is the towing tank as it relates to: modem trends in the maritime business and in naval architecture education. The primary purpose of this contribution is to solicit the comments of attendees of the 26 ATTC on our conclusions. We welcome your suggestions.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126810415","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 stationary 3-D free tip hydrofoil was constructed and tested in a water tunnel at the Marine Hydrodynamics Laboratory at the Massachusetts Institute of Technology. The foil had moderate skew and was designed to produce a tip vortex like that typically seen on a modem free tip propeller blade. At the fixed loading condition, studies on the foil and its tip vortex were collected at ca vita ting and non-cavitating conditions. Laser Doppler Velocimetry (LDV) was used to collect the tip vortex velocity profiles at various axial positions at both non-cavitating and cavitating conditions. Also using the LDV system, closed contour velocity profiles were taken at various spanwise positions and used to measure the span loading distribution. Tip vortex circulation growth and core radius growth as a function of streamwise position were extracted from the tip vortex velocity profiles. growth and core radius growth as a function of streamwise position were extracted from the tip vortex velocity profiles. Pictures were taken of the cavitating vortex as well as foil sheet cavities at inception to document cavitation observations.
{"title":"Velocity Measurements around a Cavitating Tip Vortex on a 3-D Hydrofoil using Laser Doppler Velocimetry","authors":"R. Kimball, D. Sura, M. Hamess","doi":"10.5957/attc-2001-004","DOIUrl":"https://doi.org/10.5957/attc-2001-004","url":null,"abstract":"A stationary 3-D free tip hydrofoil was constructed and tested in a water tunnel at the Marine Hydrodynamics Laboratory at the Massachusetts Institute of Technology. The foil had moderate skew and was designed to produce a tip vortex like that typically seen on a modem free tip propeller blade. At the fixed loading condition, studies on the foil and its tip vortex were collected at ca vita ting and non-cavitating conditions. Laser Doppler Velocimetry (LDV) was used to collect the tip vortex velocity profiles at various axial positions at both non-cavitating and cavitating conditions. Also using the LDV system, closed contour velocity profiles were taken at various spanwise positions and used to measure the span loading distribution. Tip vortex circulation growth and core radius growth as a function of streamwise position were extracted from the tip vortex velocity profiles. growth and core radius growth as a function of streamwise position were extracted from the tip vortex velocity profiles. Pictures were taken of the cavitating vortex as well as foil sheet cavities at inception to document cavitation observations.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128054643","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}
Current is generated at the National Research Council's Institute for Marine Dynamics, Offshore Engineering Basin (OEB) in St. John's, Newfoundland, using a pump thruster system in which flow is conveyed under a false floor and returns through the test section of basin. The objectives of this project were to quantify and assess the performance of the existing current generation system and to experimentally verify a design exit manifold for improved current generation. At present, current operation results in large-scale vertical vortices being produced at the current exit end of the basin where. the wave boards are installed. The exit flow is not confined and therefore flow divergence occurs at the vertical back wall of the basin. These conditions contribute to substantial energy losses at the exit region, which in turn result in low current velocities at the test region of the basin. Through the use of Computational Fluid Dynamics, preliminary designs for an exit manifold to reverse flow back into the basin were modeled to ensure an efficient system is implemented to dissipate the flow into the basin. The CFD models provided an insight into the shear flow turbulent mixing at the exit region. For operational reasons the design was constrained to a height of 0.35m and a maximum length of approximately 4. 0m. The final detailed design called for a contraction/expansion combination, J 80° turn with exit manifold and flow straighteners. A prototype of the design was fabricated of aluminum and experimental tests were conducted to assess its performance. The results of the experiments showed a significant improvement in current generation capabilities over the present current generation setup. For deep-water tests, the use of the prototype exit manifold resulted in a velocity magnitude increase of two times over the present setup. Shallow water tests resulted in a velocity magnitude increase of greater than three times over the present setup. It is envisaged that the installation of the exit manifold design in the OEB will significantly improve the current generation.
{"title":"Design and Experimental Verification of an Exit Manifold for Improved Current Generation in an Offshore Engineering Basin","authors":"S. Chin, B. Gerrits, B. Colboume","doi":"10.5957/attc-2001-014","DOIUrl":"https://doi.org/10.5957/attc-2001-014","url":null,"abstract":"Current is generated at the National Research Council's Institute for Marine Dynamics, Offshore Engineering Basin (OEB) in St. John's, Newfoundland, using a pump thruster system in which flow is conveyed under a false floor and returns through the test section of basin. The objectives of this project were to quantify and assess the performance of the existing current generation system and to experimentally verify a design exit manifold for improved current generation. At present, current operation results in large-scale vertical vortices being produced at the current exit end of the basin where. the wave boards are installed. The exit flow is not confined and therefore flow divergence occurs at the vertical back wall of the basin. These conditions contribute to substantial energy losses at the exit region, which in turn result in low current velocities at the test region of the basin.\u0000 Through the use of Computational Fluid Dynamics, preliminary designs for an exit manifold to reverse flow back into the basin were modeled to ensure an efficient system is implemented to dissipate the flow into the basin. The CFD models provided an insight into the shear flow turbulent mixing at the exit region. For operational reasons the design was constrained to a height of 0.35m and a maximum length of approximately 4. 0m. The final detailed design called for a contraction/expansion combination, J 80° turn with exit manifold and flow straighteners. A prototype of the design was fabricated of aluminum and experimental tests were conducted to assess its performance.\u0000 The results of the experiments showed a significant improvement in current generation capabilities over the present current generation setup. For deep-water tests, the use of the prototype exit manifold resulted in a velocity magnitude increase of two times over the present setup. Shallow water tests resulted in a velocity magnitude increase of greater than three times over the present setup. It is envisaged that the installation of the exit manifold design in the OEB will significantly improve the current generation.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114918938","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 provides results of full-scale video observations of underway cavitating propeller operation and corresponding vibration acceleration measurements taken in the stem region of the U.S. Coast Guard Seagoing Buoy Tender WLB 201 JUNIPER. Selected results are presented from two different trial periods: before and after the ship was fitted with flow improvement fins designed to deal with the very poor propeller inflow velocity distribution and the resulting troublesome inboard noise performance related to propeller cavitation. An important the objective of this work was to try to interpret the trends of ship vibration and noise responses in terms of observed propeller cavitation phenomena.
{"title":"Full-Scale Observation of Propeller Cavitation on a U.S Coast Guard Ship","authors":"M. Wilson","doi":"10.5957/attc-2001-002","DOIUrl":"https://doi.org/10.5957/attc-2001-002","url":null,"abstract":"This paper provides results of full-scale video observations of underway cavitating propeller operation and corresponding vibration acceleration measurements taken in the stem region of the U.S. Coast Guard Seagoing Buoy Tender WLB 201 JUNIPER. Selected results are presented from two different trial periods: before and after the ship was fitted with flow improvement fins designed to deal with the very poor propeller inflow velocity distribution and the resulting troublesome inboard noise performance related to propeller cavitation. An important the objective of this work was to try to interpret the trends of ship vibration and noise responses in terms of observed propeller cavitation phenomena.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128816859","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}
In September of 1998, a collaborative effort between the Institute for Marine Dynamics (IMD) of the National Research Council of Canada and the Ocean Engineering Research Centre of Memorial University of Newfoundland began to design a streamlined AUV to serve as a testbed for /MD and graduate level research. This A UV, the C-SCOUT, is expected to serve as a test-bed to assist in the development of future control and propulsion systems, the testing of vehicle components, and as a general research and development tool for years to come. Future versions of C-SCOUT can be configured for a wide variety of missions including search and survey, under ice operations, iceberg profiling, oceanographic sampling, and mine detection and countermeasures.
{"title":"Maneuvering of the C-SCOUT AUV","authors":"T. Curtis, D. Perrault, C. Williams, N. Bose","doi":"10.5957/attc-2001-011","DOIUrl":"https://doi.org/10.5957/attc-2001-011","url":null,"abstract":"In September of 1998, a collaborative effort between the Institute for Marine Dynamics (IMD) of the National Research Council of Canada and the Ocean Engineering Research Centre of Memorial University of Newfoundland began to design a streamlined AUV to serve as a testbed for /MD and graduate level research. This A UV, the C-SCOUT, is expected to serve as a test-bed to assist in the development of future control and propulsion systems, the testing of vehicle components, and as a general research and development tool for years to come. Future versions of C-SCOUT can be configured for a wide variety of missions including search and survey, under ice operations, iceberg profiling, oceanographic sampling, and mine detection and countermeasures.","PeriodicalId":107471,"journal":{"name":"Day 1 Mon, July 23, 2001","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133716189","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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