{"title":"Notes from Abroad","authors":"J. Breslin","doi":"10.2307/933602","DOIUrl":"https://doi.org/10.2307/933602","url":null,"abstract":"","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128599917","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 frequency dependent heave, pitch, sway, and yaw hydrodynamic coefficients associated with an oscillating ellipsoid traveling with forward speed in the free surface are evaluated from a three-dimensio nal potential flow analysis. The free-surface boundary condition in the mathematical model either includes the influence of forward speed or is simplified to the equivalent zero speed case. This variation produces a velocity potential which is either frequency and speed dependent or just frequency dependent. The influence of forward speed on all the hydrodynamic coefficients is discussed.
{"title":"Hydrodynamic coefficients of an oscillating ellipsoid moving in the free surface","authors":"R. Inglis, W. Price","doi":"10.2514/3.48179","DOIUrl":"https://doi.org/10.2514/3.48179","url":null,"abstract":"The frequency dependent heave, pitch, sway, and yaw hydrodynamic coefficients associated with an oscillating ellipsoid traveling with forward speed in the free surface are evaluated from a three-dimensio nal potential flow analysis. The free-surface boundary condition in the mathematical model either includes the influence of forward speed or is simplified to the equivalent zero speed case. This variation produces a velocity potential which is either frequency and speed dependent or just frequency dependent. The influence of forward speed on all the hydrodynamic coefficients is discussed.","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115709173","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}
{"title":"Wedge Effect on Planing Hulls","authors":"Chun‐Tsung Wang","doi":"10.2514/3.48182","DOIUrl":"https://doi.org/10.2514/3.48182","url":null,"abstract":"","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114596735","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}
Appendages on underwater vehicles are often given a cross-sectional profile that will produce low drag. The potential danger is that if the profile shape is not selected carefully, the structural integrity of the appendage may be endangered by hydroelastic instability. While static divergence is usually investigated, the potential for divergent oscillations leading to destructive amplitudes is not recognized as readily. Structural damping, which often is a saving feature for wind-induced loads, plays a completely insignificant role in a high-density fluid such as water. The unsteady hydrodynamic characteristics leading to self-excited oscillations are derived analytically and the means by which the dynamic instability can be minimized or eliminated are described.
{"title":"Potential Hydroelastic Instability of Profiled Underwater Structures","authors":"L. Ericsson, J. Redding","doi":"10.2514/3.63191","DOIUrl":"https://doi.org/10.2514/3.63191","url":null,"abstract":"Appendages on underwater vehicles are often given a cross-sectional profile that will produce low drag. The potential danger is that if the profile shape is not selected carefully, the structural integrity of the appendage may be endangered by hydroelastic instability. While static divergence is usually investigated, the potential for divergent oscillations leading to destructive amplitudes is not recognized as readily. Structural damping, which often is a saving feature for wind-induced loads, plays a completely insignificant role in a high-density fluid such as water. The unsteady hydrodynamic characteristics leading to self-excited oscillations are derived analytically and the means by which the dynamic instability can be minimized or eliminated are described.","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"5 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132394717","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}
Adaptation of the friction and wave drag components to the classic aerodynamic drag polar are shown with accommodation for the weight/center-of-gravity envelope. The parametric forms of the drag, power, and specific range and endurance curves are shown and related to the traditional dimensional forms. The relationship between the drag polar and the propulsion is indicated.
{"title":"Hydrofoil Craft Drag Polar","authors":"H. R. Wright, F. Otto","doi":"10.2514/3.48180","DOIUrl":"https://doi.org/10.2514/3.48180","url":null,"abstract":"Adaptation of the friction and wave drag components to the classic aerodynamic drag polar are shown with accommodation for the weight/center-of-gravity envelope. The parametric forms of the drag, power, and specific range and endurance curves are shown and related to the traditional dimensional forms. The relationship between the drag polar and the propulsion is indicated.","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129312178","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}
Simple power laws governing the rate of spread of oil slicks on water are derived after relaxing two restrictive assumptions made in the analyses existing in the literature, namely that of an instantaneous release of the oil and that of laminar flow in the underlying water layers. Hydrodynamic forces acting on the slick are discussed, as are the effects of ambient turbulence. It is found that the simple phenomenological and order-of-magnitude arguments used here do not yield the values of the numerical coefficients in the power law relationships. Instead, the values of these coefficients have to be determined from data obtained in laboratory experiments.
{"title":"Spread of Oil Slicks on a Natural Body of Water","authors":"T. Sundaram","doi":"10.2514/3.63192","DOIUrl":"https://doi.org/10.2514/3.63192","url":null,"abstract":"Simple power laws governing the rate of spread of oil slicks on water are derived after relaxing two restrictive assumptions made in the analyses existing in the literature, namely that of an instantaneous release of the oil and that of laminar flow in the underlying water layers. Hydrodynamic forces acting on the slick are discussed, as are the effects of ambient turbulence. It is found that the simple phenomenological and order-of-magnitude arguments used here do not yield the values of the numerical coefficients in the power law relationships. Instead, the values of these coefficients have to be determined from data obtained in laboratory experiments.","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122566852","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}
{"title":"Self-induced separation of flow in a hydrodynamic scoop","authors":"G. Hokenson","doi":"10.2514/3.48183","DOIUrl":"https://doi.org/10.2514/3.48183","url":null,"abstract":"","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121107683","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}
{"title":"Inviscid parallel flow stability with mean profile distortion","authors":"W. Chin","doi":"10.2514/3.48178","DOIUrl":"https://doi.org/10.2514/3.48178","url":null,"abstract":"","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114689430","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}
Introduction T feasibility of the development of a vehicle based on wing-in-ground (WIG) effect principles has intrigued military and cargo transportation planners for nearly 20 years. These vehicles could be developed for antisubmarine warfare (ASW) or transportation roles. In the U.S. several studies were conducted in the late 1950's and early 1960's to determine the feasibility of developing large transoceanic cargo transport vehicles. However, the decision to develop the Lockheed C-5A large jet cargo transport curtailed these activities. In the 1970's, interest in the WIG phenomenon was revived primarily in response to the need to identify new modes of transportation that would provide an energyefficient, cost-effective transport vehicle. This requirement was highlighted by the energy crisis of 1973. The Soviet Union has maintained a continuing interest in WIG vehicles since the 1960's. In the early 1960's, the Ministry of Ship Building conducted extensive studies of WIGs as transportation vehicles and several experimental vehicles were built. The most recent Soviet experimental designs have been suggested as search-and-rescue vehicles in river and coastal waters." This paper is an historical review of WIG vehicles. Experimental and proposed designs are described. Some comparisons are made betweeen these vehicles and more conventional transport vehicles. Some conclusions are drawn as to the future of WIG technology and its application to military and civilian vehicle requirements.
{"title":"Historical Review of WIG Vehicles","authors":"R. Ollila","doi":"10.2514/3.63187","DOIUrl":"https://doi.org/10.2514/3.63187","url":null,"abstract":"Introduction T feasibility of the development of a vehicle based on wing-in-ground (WIG) effect principles has intrigued military and cargo transportation planners for nearly 20 years. These vehicles could be developed for antisubmarine warfare (ASW) or transportation roles. In the U.S. several studies were conducted in the late 1950's and early 1960's to determine the feasibility of developing large transoceanic cargo transport vehicles. However, the decision to develop the Lockheed C-5A large jet cargo transport curtailed these activities. In the 1970's, interest in the WIG phenomenon was revived primarily in response to the need to identify new modes of transportation that would provide an energyefficient, cost-effective transport vehicle. This requirement was highlighted by the energy crisis of 1973. The Soviet Union has maintained a continuing interest in WIG vehicles since the 1960's. In the early 1960's, the Ministry of Ship Building conducted extensive studies of WIGs as transportation vehicles and several experimental vehicles were built. The most recent Soviet experimental designs have been suggested as search-and-rescue vehicles in river and coastal waters.\" This paper is an historical review of WIG vehicles. Experimental and proposed designs are described. Some comparisons are made betweeen these vehicles and more conventional transport vehicles. Some conclusions are drawn as to the future of WIG technology and its application to military and civilian vehicle requirements.","PeriodicalId":157493,"journal":{"name":"Journal of Hydronautics","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1980-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130651446","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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