IOWA INST OF HYDRAULIC RESEARCH IOWA CITY
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Works:  139 works in 143 publications in 1 language and 150 library holdings 

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IOWA INST OF HYDRAULIC RESEARCH IOWA CITY
Viscous Effect on Ship Wave Resistance(
Book
)
1 edition published in 1983 in English and held by 3 WorldCat member libraries worldwide
Topics contained in this report are: (1) The methods of conformal mapping and analytic continuation are applied to obtain slenderbody centerplane distributions; and (2) Three closedform approximations to the doubleintegral 'near field' term in the Havelock Green function are derived. An application to centerplane source distributions for shipwave problems is discussed
1 edition published in 1983 in English and held by 3 WorldCat member libraries worldwide
Topics contained in this report are: (1) The methods of conformal mapping and analytic continuation are applied to obtain slenderbody centerplane distributions; and (2) Three closedform approximations to the doubleintegral 'near field' term in the Havelock Green function are derived. An application to centerplane source distributions for shipwave problems is discussed
Calculation of the viscous resistance of bodies of revolution by A Nakayama(
Book
)
1 edition published in 1973 in English and held by 3 WorldCat member libraries worldwide
The flow in the tail region of a body of revolution is a complex one since there the boundary layer often grows to a thickness many times the local radius of the body and there results a strong interaction between the boundary layer and the external potential flow. The influence of making simplifying assumptions concerning the flow in this region in conventional dragcalculation methods is discussed, and assessed by incorporating a method which takes into account the effects of the thick axisymmetric boundarylayer near the tail in an approximate manner. It is shown that this modification leads to a dragcalculation method which gives consistently accurate prediction of the viscous resistance of a wide variety of bodies of revolution. (Author)
1 edition published in 1973 in English and held by 3 WorldCat member libraries worldwide
The flow in the tail region of a body of revolution is a complex one since there the boundary layer often grows to a thickness many times the local radius of the body and there results a strong interaction between the boundary layer and the external potential flow. The influence of making simplifying assumptions concerning the flow in this region in conventional dragcalculation methods is discussed, and assessed by incorporating a method which takes into account the effects of the thick axisymmetric boundarylayer near the tail in an approximate manner. It is shown that this modification leads to a dragcalculation method which gives consistently accurate prediction of the viscous resistance of a wide variety of bodies of revolution. (Author)
Effects of waves on the boundary layer of a surfacepiercing body by
Frederick Stern(
Book
)
2 editions published between 1985 and 1987 in English and held by 2 WorldCat member libraries worldwide
The boundaryvalue problem associated with the boundarylayer development on a surfacepiercing body is formulated in a rigorous manner in which proper consideration is given both to the kinematic and dynamic boundary conditions and to the deformation of the potentialflow free surface within the boundary layer. Simplifications that are appropriate for small amplitude waves are then investigated. The flow flow field in the neighborhood of the bodyboundarylayer/freesurface juncture is divided into five regions and orderofmagnitude estimated for each region are provided. Of particular interest is the body/freesurface boundary layer in the region very close to the free surface in which the freesurface boundary conditions have a significant influence. In this region, it is shown that, for laminar flow, the parameter Ak/e (where Ak is the wavesteepness parameter and e = delta/L is the nondimensional boundarylayer thickness) is an important parameter for characterizing the flow. Different solution regimes are identified depending on the magnitude of Ak/e. In particular, for Ak/e sufficiently large such that the freesurface boundary conditions have a significant influence a consistent formulation requires the solution of the partiallyparabolic NavierStokes equations. For turbulent flow, these conclusions cannot be reached with the same degree of certainty due to the present uncertainties in turbulence modelling, especially when a free surface is present. Numerical results are provided for the idealized geometry of a combination Stokeswave/flatplate. Keywords: Wave/boundary layer interaction; 3D boundary layer; Ship boundary layer
2 editions published between 1985 and 1987 in English and held by 2 WorldCat member libraries worldwide
The boundaryvalue problem associated with the boundarylayer development on a surfacepiercing body is formulated in a rigorous manner in which proper consideration is given both to the kinematic and dynamic boundary conditions and to the deformation of the potentialflow free surface within the boundary layer. Simplifications that are appropriate for small amplitude waves are then investigated. The flow flow field in the neighborhood of the bodyboundarylayer/freesurface juncture is divided into five regions and orderofmagnitude estimated for each region are provided. Of particular interest is the body/freesurface boundary layer in the region very close to the free surface in which the freesurface boundary conditions have a significant influence. In this region, it is shown that, for laminar flow, the parameter Ak/e (where Ak is the wavesteepness parameter and e = delta/L is the nondimensional boundarylayer thickness) is an important parameter for characterizing the flow. Different solution regimes are identified depending on the magnitude of Ak/e. In particular, for Ak/e sufficiently large such that the freesurface boundary conditions have a significant influence a consistent formulation requires the solution of the partiallyparabolic NavierStokes equations. For turbulent flow, these conclusions cannot be reached with the same degree of certainty due to the present uncertainties in turbulence modelling, especially when a free surface is present. Numerical results are provided for the idealized geometry of a combination Stokeswave/flatplate. Keywords: Wave/boundary layer interaction; 3D boundary layer; Ship boundary layer
Further investigations on components of ship resistance final report by
L Landweber(
Book
)
2 editions published between 1974 and 1975 in English and held by 2 WorldCat member libraries worldwide
The accomplishments during the eleventh year of research on components of ship resistance, supplementing that reported in IIHR Report No. 162 on the first 10 years, are summarized. These include the derivation of a more exact formula for calculating the viscous drag of a ship model from wakesurvey measurements, a refinement of a procedure for determining wave resistance from surfaceprofile measurements, studies of the effect of the wake on waveresistance measurements, and some contributions to the problem of correcting resistance measurements for the influence of tank boundaries
2 editions published between 1974 and 1975 in English and held by 2 WorldCat member libraries worldwide
The accomplishments during the eleventh year of research on components of ship resistance, supplementing that reported in IIHR Report No. 162 on the first 10 years, are summarized. These include the derivation of a more exact formula for calculating the viscous drag of a ship model from wakesurvey measurements, a refinement of a procedure for determining wave resistance from surfaceprofile measurements, studies of the effect of the wake on waveresistance measurements, and some contributions to the problem of correcting resistance measurements for the influence of tank boundaries
Viscousinviscid interaction with higherorder viscousflow equations by
Frederick Stern(
Book
)
2 editions published between 1986 and 1987 in English and held by 2 WorldCat member libraries worldwide
The partiallyparabolic, or parabolised, NavierStokes equations for laminar flow, and the corresponding Reynolds equations for turbulent flow, are coupled with an inviscidflow solution procedure to develop a viscousinviscid interaction method which can be used threedimensional flows which cannot be treated by means of the classical boundarylayer equations. Potential applications of such a higherorder matching procedure include thick layers (wakes, wall jets), solidsolid and solidfluid corners. This report provides a detailed overview of the approach for general 3D flows and presents the results of applications to some simple test cases. The Reynolds equations are derived in nonorthogonal curvilinear coordinates, with velocity components along the coordinate directions, using vector techniques. This approach differs from the commonlyused tensor method but serves to establish a connection with the more familiar boundary layer methods. The kepsilon model is used for turbulent flows. The partiallyparabolic viscousflow equations are solved using an implicit finitedifference scheme and the SIMPLER algorithm for pressurevelocity coupling. The inviscidflow solutions are obtained with a conforming panel, sourcepanel method. Interaction between the viscous and inviscid regions is accounted for using the displacement body concept
2 editions published between 1986 and 1987 in English and held by 2 WorldCat member libraries worldwide
The partiallyparabolic, or parabolised, NavierStokes equations for laminar flow, and the corresponding Reynolds equations for turbulent flow, are coupled with an inviscidflow solution procedure to develop a viscousinviscid interaction method which can be used threedimensional flows which cannot be treated by means of the classical boundarylayer equations. Potential applications of such a higherorder matching procedure include thick layers (wakes, wall jets), solidsolid and solidfluid corners. This report provides a detailed overview of the approach for general 3D flows and presents the results of applications to some simple test cases. The Reynolds equations are derived in nonorthogonal curvilinear coordinates, with velocity components along the coordinate directions, using vector techniques. This approach differs from the commonlyused tensor method but serves to establish a connection with the more familiar boundary layer methods. The kepsilon model is used for turbulent flows. The partiallyparabolic viscousflow equations are solved using an implicit finitedifference scheme and the SIMPLER algorithm for pressurevelocity coupling. The inviscidflow solutions are obtained with a conforming panel, sourcepanel method. Interaction between the viscous and inviscid regions is accounted for using the displacement body concept
Suspended sediment modeling of dredgedisposal effluent in the GREATII study reach(
Book
)
1 edition published in 1980 in English and held by 2 WorldCat member libraries worldwide
The objectives of this study were to: (1) Collect field data on suspended solids and turbidity during two dredge disposal operations on the Mississippi River; (2) Check the utility of the Schubel and Carter (1978) model for adequately describing the observed field data and modify, if possible, to reflect river conditions; (3) Examine other models available to describe the observed field data, including the numerical, computer solution of Weschler and Cogley (1977) (such models can be used to rapidly generate a number of simulations covering a spectrum of conditions expected in the Mississippi River); and (4) Develop a convenient, analytical solution for the prediction of suspended solids concentrations caused by hydraulically dredged sediment and compare the model results to field measurements. The scope of this modeling effort includes the utilization of existing dredge disposal mathematical models, both analytical and numerical, as well as the development of a new model. The new model is specifically derived for continuous nonpoint source, sidebank disposal type of operations such as commonly practiced in the upper Mississippi River. Suspended solids concentrations are predicted. This research grew out of a larger dredging study by a multidepartmental, multidisciplinary consortium called the Great River Environmental Action Team, GREAT II. The GREAT II study reach of the Mississippi River stretches from Guttenberg, Iowa to Saverton, Missouri
1 edition published in 1980 in English and held by 2 WorldCat member libraries worldwide
The objectives of this study were to: (1) Collect field data on suspended solids and turbidity during two dredge disposal operations on the Mississippi River; (2) Check the utility of the Schubel and Carter (1978) model for adequately describing the observed field data and modify, if possible, to reflect river conditions; (3) Examine other models available to describe the observed field data, including the numerical, computer solution of Weschler and Cogley (1977) (such models can be used to rapidly generate a number of simulations covering a spectrum of conditions expected in the Mississippi River); and (4) Develop a convenient, analytical solution for the prediction of suspended solids concentrations caused by hydraulically dredged sediment and compare the model results to field measurements. The scope of this modeling effort includes the utilization of existing dredge disposal mathematical models, both analytical and numerical, as well as the development of a new model. The new model is specifically derived for continuous nonpoint source, sidebank disposal type of operations such as commonly practiced in the upper Mississippi River. Suspended solids concentrations are predicted. This research grew out of a larger dredging study by a multidepartmental, multidisciplinary consortium called the Great River Environmental Action Team, GREAT II. The GREAT II study reach of the Mississippi River stretches from Guttenberg, Iowa to Saverton, Missouri
Experimental study of the wavemaking of horizontallyoriented vorticity in a wake by
A Swain(
Book
)
1 edition published in 1974 in English and held by 2 WorldCat member libraries worldwide
Towingtank experiments were conducted in order to investigate the wavemaking of horizontallyoriented vorticity in a wake. It was found that the amplitudes of the surface disturbance, measured with three capacitance wires, were about one tenth of those generated by a ship model of the same length and Froude number. Furthermore, the wave resistance was about one percent of that obtained for a Series60 model of the same wettedsurface area. (Author)
1 edition published in 1974 in English and held by 2 WorldCat member libraries worldwide
Towingtank experiments were conducted in order to investigate the wavemaking of horizontallyoriented vorticity in a wake. It was found that the amplitudes of the surface disturbance, measured with three capacitance wires, were about one tenth of those generated by a ship model of the same length and Froude number. Furthermore, the wave resistance was about one percent of that obtained for a Series60 model of the same wettedsurface area. (Author)
GREAT II Upper Mississippi River (Guttenberg, Iowa to Saverton, Missouri) Water Quality Work Group Appendix(
Book
)
1 edition published in 1980 in English and held by 2 WorldCat member libraries worldwide
The study programs and recommendations of the three GREAT Teams will be brought together into a river management strategy for the entire Upper Mississippi River. The goal of the study is to present to Congress and the people a river resource management plan that is, above all, realistic  a plan that is technically and economically sound, socially and environmentally acceptable, and capable of being put into action within a reasonable period of time
1 edition published in 1980 in English and held by 2 WorldCat member libraries worldwide
The study programs and recommendations of the three GREAT Teams will be brought together into a river management strategy for the entire Upper Mississippi River. The goal of the study is to present to Congress and the people a river resource management plan that is, above all, realistic  a plan that is technically and economically sound, socially and environmentally acceptable, and capable of being put into action within a reasonable period of time
Orthogonal coordinate systems for threedimensional boundary layers : with particular reference to ship forms by
Touvia Miloh(
Book
)
1 edition published in 1972 in English and held by 1 WorldCat member library worldwide
The problem of choosing orthogonal, curvilinear, coordinate systems for use in boundarylayer calculations on arbitrary threedimensional bodies is considered in some detail. A general method for the practical evaluation of the various geometrical properties of the coordinates occurring in the threedimensional boundarylayer equations is described. A particular coordinate system which appears to be the most convenient one for ship hulls is then proposed and analyzed further
1 edition published in 1972 in English and held by 1 WorldCat member library worldwide
The problem of choosing orthogonal, curvilinear, coordinate systems for use in boundarylayer calculations on arbitrary threedimensional bodies is considered in some detail. A general method for the practical evaluation of the various geometrical properties of the coordinates occurring in the threedimensional boundarylayer equations is described. A particular coordinate system which appears to be the most convenient one for ship hulls is then proposed and analyzed further
Coralville water quality study annual report : water year October 1, 1975 to September 30, 1976 by
Donald B McDonald(
Book
)
1 edition published in 1979 in English and held by 1 WorldCat member library worldwide
The Coralville Reservoir Water Quality Project was initiated in 1964 and has continued without interruption since that time. The purpose of the study has been the determination of the effects of a flood control reservoir on the chemical and biological characteristics of its parent river. Samples were collected from the Iowa River upstream from the reservoir; at Johnson County Road W8 (formerly '0'); from the top, middepth and bottom at the reservoir at the Mehaffey Bridge downstream from the Lake MacBride spillway; and from the Iowa River at two points downstream from the reservoir about one mile below the Coralville dam and at the University of Iowa Water Treatment Plant. During the current water year, samples were collected on a weekly basis and analyzed for temperature, conductivity, turbidity, dissolved oxygen, Ph, carbon dioxide, alkalinity, ammonia and orthophosphate. All other parameters, including plankton, were determined on a twice monthly basis
1 edition published in 1979 in English and held by 1 WorldCat member library worldwide
The Coralville Reservoir Water Quality Project was initiated in 1964 and has continued without interruption since that time. The purpose of the study has been the determination of the effects of a flood control reservoir on the chemical and biological characteristics of its parent river. Samples were collected from the Iowa River upstream from the reservoir; at Johnson County Road W8 (formerly '0'); from the top, middepth and bottom at the reservoir at the Mehaffey Bridge downstream from the Lake MacBride spillway; and from the Iowa River at two points downstream from the reservoir about one mile below the Coralville dam and at the University of Iowa Water Treatment Plant. During the current water year, samples were collected on a weekly basis and analyzed for temperature, conductivity, turbidity, dissolved oxygen, Ph, carbon dioxide, alkalinity, ammonia and orthophosphate. All other parameters, including plankton, were determined on a twice monthly basis
Fully Developed Periodic Turbulent Pipe Flow. Part 2. The Detailed Structure of the Flow(
Book
)
1 edition published in 1983 in English and held by 1 WorldCat member library worldwide
1 edition published in 1983 in English and held by 1 WorldCat member library worldwide
Detailed model study of pumpapproach flows for the Lake Chicot pumping plant by
Tatsuaki Nakato(
Book
)
2 editions published in 1977 in English and held by 1 WorldCat member library worldwide
A 1:24 Froudescale model of the proposed Lake Chicot Pumping Station was constructed and utilized to identify and to correct hydraulically objectionable features of the flows in the pump sumps. The model tests showed that the flows from the plant forebay generally enter the individual pump bays with a strong transverse component of velocity and produce an intense captive eddy on the lee side of each pumpbay partition wall. The transverse velocity resulted from geometric constraints imposed on the plant configuration. In order to achieve better pump approachflow conditions trash racks with relatively deep vertical bars which functioned as turning vanes were proposed. A 1:10scale sump model then was built to test for modelscale effects in the trashrack tests, and an extensive study was conducted to obtain an improved sump configuration which would minimize any vortexrelated problems in and around pump suction bells. The modified sump configuration has small clearance between the pump bell and sump backwall; converging sidewalls; and a floor mounted splitter plate (vortex breaker) beneath the pump. (Author)
2 editions published in 1977 in English and held by 1 WorldCat member library worldwide
A 1:24 Froudescale model of the proposed Lake Chicot Pumping Station was constructed and utilized to identify and to correct hydraulically objectionable features of the flows in the pump sumps. The model tests showed that the flows from the plant forebay generally enter the individual pump bays with a strong transverse component of velocity and produce an intense captive eddy on the lee side of each pumpbay partition wall. The transverse velocity resulted from geometric constraints imposed on the plant configuration. In order to achieve better pump approachflow conditions trash racks with relatively deep vertical bars which functioned as turning vanes were proposed. A 1:10scale sump model then was built to test for modelscale effects in the trashrack tests, and an extensive study was conducted to obtain an improved sump configuration which would minimize any vortexrelated problems in and around pump suction bells. The modified sump configuration has small clearance between the pump bell and sump backwall; converging sidewalls; and a floor mounted splitter plate (vortex breaker) beneath the pump. (Author)
An investigation of the total sediment load by
Emmett M Laursen(
Book
)
1 edition published in 1957 in English and held by 1 WorldCat member library worldwide
1 edition published in 1957 in English and held by 1 WorldCat member library worldwide
Effect of wake on wave resistance of a ship model by
Marguerite Moreno(
Book
)
1 edition published in 1975 in English and held by 1 WorldCat member library worldwide
For the purpose of resolving the question of the influence of its wake on the wavemaking resistance of a ship, the total, viscous and wavemaking resistance of a Series 60 ship model were measured with the wetted surface first smooth, and then rough. It was found that the wave resistance was significantly less with the rough surface, implying that viscous effects should not be neglected in the development of higherorder wave theory. Since the wakesurvey method was used to determine the viscous resistance, the opportunity was taken to compare the results with roughness with the values obtained by calculating the boundary layer on the rough 'equivalent' body of revolution, with satisfactory agreement
1 edition published in 1975 in English and held by 1 WorldCat member library worldwide
For the purpose of resolving the question of the influence of its wake on the wavemaking resistance of a ship, the total, viscous and wavemaking resistance of a Series 60 ship model were measured with the wetted surface first smooth, and then rough. It was found that the wave resistance was significantly less with the rough surface, implying that viscous effects should not be neglected in the development of higherorder wave theory. Since the wakesurvey method was used to determine the viscous resistance, the opportunity was taken to compare the results with roughness with the values obtained by calculating the boundary layer on the rough 'equivalent' body of revolution, with satisfactory agreement
Viscous flow over ship sterns by
V. C Patel(
Book
)
1 edition published in 1985 in English and held by 1 WorldCat member library worldwide
When this research project was initiated in October 1980, it was evident that neither reliable calculation methods nor a comprehensive set of data existed for the description of the complex viscous flow over the stern and in the wake of the ship hull. The 1980 SSPAITTC Workshop on Ship Boundary Layers (Larsson, 1981) had indicated that all available methods for the calculation of thin boundary layers broke down, for a variety of reasons, in the stern region. At about the same time, the author (Patel, 1980) reviewed previous experimental investigations in wake flows for the Standard Conferences on Complex Turbulent Shear Flows and concluded that there was not a single set of reliable and detailed data for threedimensional stern and wake flows which could be used as a test case for the assessment of calculation methods for such flows. This investigation was therefore undertaken with three specific objectives: (1) To develop promising threedimensional thin boundarylayer calculation methods for application to arbitrary ship hulls and assess their limitations; (2) To develop a calculation procedure for the flow over the stern and in the wake of the ship; and (3) To conduct a comprehensive, windtunnel experiment on a ship doublemodel to document, in detail, the mean flow and turbulence in the thick stern boundary layer and the near wake. Additional keywords: Stern flow; Turbulent flow; Navier Strokes equations
1 edition published in 1985 in English and held by 1 WorldCat member library worldwide
When this research project was initiated in October 1980, it was evident that neither reliable calculation methods nor a comprehensive set of data existed for the description of the complex viscous flow over the stern and in the wake of the ship hull. The 1980 SSPAITTC Workshop on Ship Boundary Layers (Larsson, 1981) had indicated that all available methods for the calculation of thin boundary layers broke down, for a variety of reasons, in the stern region. At about the same time, the author (Patel, 1980) reviewed previous experimental investigations in wake flows for the Standard Conferences on Complex Turbulent Shear Flows and concluded that there was not a single set of reliable and detailed data for threedimensional stern and wake flows which could be used as a test case for the assessment of calculation methods for such flows. This investigation was therefore undertaken with three specific objectives: (1) To develop promising threedimensional thin boundarylayer calculation methods for application to arbitrary ship hulls and assess their limitations; (2) To develop a calculation procedure for the flow over the stern and in the wake of the ship; and (3) To conduct a comprehensive, windtunnel experiment on a ship doublemodel to document, in detail, the mean flow and turbulence in the thick stern boundary layer and the near wake. Additional keywords: Stern flow; Turbulent flow; Navier Strokes equations
DRAG COEFFICIENTS OF SUPERCAVITATING BODIES OF REVOLUTION AT VARIOUS ANGLES OF YAW(
)
1 edition published in 1963 in English and held by 0 WorldCat member libraries worldwide
In order to supplement the limited data so far discovered, the evaluation of the drag coefficients of various head forms under cavitating conditions at various angles of yaw, from the measured values of the pressure distribution, was undertaken. The aforementioned pressure distributions for zero angle of yaw were published by the Iowa Institute of Hydraulic Research, in 1948. Eight of the head forms included in these first tests were selected for a further study of pressure distribution under cavitating conditions at angles of yaw and the results were published in 1962. The latter also included pressure distribution measurements at zero angle of yaw. The results obtained for the drag coefficients of the various head forms at several yaw angles are presented and compared with the directly measured values for the drag at zero angle of yaw available in the literature. No data on direct measurements of drag at angles of yaw have been found
1 edition published in 1963 in English and held by 0 WorldCat member libraries worldwide
In order to supplement the limited data so far discovered, the evaluation of the drag coefficients of various head forms under cavitating conditions at various angles of yaw, from the measured values of the pressure distribution, was undertaken. The aforementioned pressure distributions for zero angle of yaw were published by the Iowa Institute of Hydraulic Research, in 1948. Eight of the head forms included in these first tests were selected for a further study of pressure distribution under cavitating conditions at angles of yaw and the results were published in 1962. The latter also included pressure distribution measurements at zero angle of yaw. The results obtained for the drag coefficients of the various head forms at several yaw angles are presented and compared with the directly measured values for the drag at zero angle of yaw available in the literature. No data on direct measurements of drag at angles of yaw have been found
Interaction and impact of floating bodies by
A. T Chwang(
)
1 edition published in 1992 in English and held by 0 WorldCat member libraries worldwide
On the basis of two 1983 OPNAV instructions, S34705A entitled 'U.S. Navy Policy Regarding Arctic Polar Region' and S3470.6 entitled 'U.S. Navy Warfare Program', the U.S. Navy is preparing to operate its surface ships at high latitudes on a routine basis in support of the nation's Maritime Strategy. In addressing these operating requirements, the U.S. Navy must evaluate the ability of its surface ships to fulfill their mission when operating near the ice edge in the marginal ice zone, and when entering an ice covered port with icebreaker assistance. As the Arctic has become a principal strategic location, knowledge and prediction of seaice conditions and the ability to cope with them have become essential to the U.S. Navy. The longterm goal of our research project is to investigate the hydrodynamic interactions, including central and oblique impact, between two floating bodies, or between a floating body and a fixed body. The floating body is usually an ice floe, and the fixed body is an offshore structure. Our nearterm objectives are to develop a rationally formulated, computerbased analytical model of farfield icefloe trajectories and nearfield hydrodynamic interactions between floating ice floes and offshore structures. The offshore structures considered in the present study would be assumed to have the shape of a circular cylinder. The ice floes would have the shape of a rectangular block, a rectangular cylinder, a circular cylinder, a circular disk, or a sphere. The analysis would be based on the equations of planar motion of an ice floe under the action of external forces due to wind, fluid viscosity, fluid inertia, and the nonuniformity of the flow field due to the presence of the offshore structures
1 edition published in 1992 in English and held by 0 WorldCat member libraries worldwide
On the basis of two 1983 OPNAV instructions, S34705A entitled 'U.S. Navy Policy Regarding Arctic Polar Region' and S3470.6 entitled 'U.S. Navy Warfare Program', the U.S. Navy is preparing to operate its surface ships at high latitudes on a routine basis in support of the nation's Maritime Strategy. In addressing these operating requirements, the U.S. Navy must evaluate the ability of its surface ships to fulfill their mission when operating near the ice edge in the marginal ice zone, and when entering an ice covered port with icebreaker assistance. As the Arctic has become a principal strategic location, knowledge and prediction of seaice conditions and the ability to cope with them have become essential to the U.S. Navy. The longterm goal of our research project is to investigate the hydrodynamic interactions, including central and oblique impact, between two floating bodies, or between a floating body and a fixed body. The floating body is usually an ice floe, and the fixed body is an offshore structure. Our nearterm objectives are to develop a rationally formulated, computerbased analytical model of farfield icefloe trajectories and nearfield hydrodynamic interactions between floating ice floes and offshore structures. The offshore structures considered in the present study would be assumed to have the shape of a circular cylinder. The ice floes would have the shape of a rectangular block, a rectangular cylinder, a circular cylinder, a circular disk, or a sphere. The analysis would be based on the equations of planar motion of an ice floe under the action of external forces due to wind, fluid viscosity, fluid inertia, and the nonuniformity of the flow field due to the presence of the offshore structures
Analysis of Sacramento River bend flows, and development of a new method for bank protection by
A. Jacob Odgaard(
)
1 edition published in 1982 in English and held by 0 WorldCat member libraries worldwide
This study includes an investigation of analytical models for the description of flow and bed charactersitics in a bend of the Sacramento River, California; and a study of a proposed new technique for bank protection. Existing models for the prediction of the steadystate transverse bed profile in channel bends are reviewed; and alternative models are developed and validated. The new models predict the transverse bed slope tovary linearly with d/r (the ratio of depth, d, to radius curvature, r) and almost linearly with the sedimentparticle Froude number. Equations for the transverse variation of depthaveraged' velocity and meangrain size also are developed, which, together with the equations for the transverse variation of depth, can provide a guide to the depth of bed erosion and depthaveraged velocity near the outer bank of river bends. It is shown, theoretically and by a physical model, that short, vertical, submerged vanes installed at incidence to the channel axis in the outer banks of a riverbend channel significantly reduce the secondary currents and the attendant undermining and highvelocity attack of the outer bank. The effect of the vanes on the secondary flow is estimated by a simple torque calculation using the. KuttaJoukowski theorem. A design relation for the van spacing is derived by equating the torque, about the channel centroid, produced by the flow curvature to that resulting from the lateral force exerted on the vanes. The relation is verified in an idealized, physical model of the mentioned bend of the Sacramento River, Calif
1 edition published in 1982 in English and held by 0 WorldCat member libraries worldwide
This study includes an investigation of analytical models for the description of flow and bed charactersitics in a bend of the Sacramento River, California; and a study of a proposed new technique for bank protection. Existing models for the prediction of the steadystate transverse bed profile in channel bends are reviewed; and alternative models are developed and validated. The new models predict the transverse bed slope tovary linearly with d/r (the ratio of depth, d, to radius curvature, r) and almost linearly with the sedimentparticle Froude number. Equations for the transverse variation of depthaveraged' velocity and meangrain size also are developed, which, together with the equations for the transverse variation of depth, can provide a guide to the depth of bed erosion and depthaveraged velocity near the outer bank of river bends. It is shown, theoretically and by a physical model, that short, vertical, submerged vanes installed at incidence to the channel axis in the outer banks of a riverbend channel significantly reduce the secondary currents and the attendant undermining and highvelocity attack of the outer bank. The effect of the vanes on the secondary flow is estimated by a simple torque calculation using the. KuttaJoukowski theorem. A design relation for the van spacing is derived by equating the torque, about the channel centroid, produced by the flow curvature to that resulting from the lateral force exerted on the vanes. The relation is verified in an idealized, physical model of the mentioned bend of the Sacramento River, Calif
Fluid and Thermodynamic Characteristics of Compressible Recoil Mechanism(
)
1 edition published in 1979 in English and held by 0 WorldCat member libraries worldwide
Fluid dynamic aspect of recoil mechanisms is studied with simple one dimensional analysis as well as two dimensional numerical analysis. Method and procedure for experimental simulation is given. Full scale and reduced scale simulation is analyzed for its advantages and disadvantages. A new numerical scheme called 'finite differential' method is developed to solve the two dimensional unsteady NavierStokes equation. The new method utilizes the local analytical solution of the total problem. The solution of the problem is obtained by assembling the local analytic solution. The method is shown to be capable of solving flows with high Reynolds numbers
1 edition published in 1979 in English and held by 0 WorldCat member libraries worldwide
Fluid dynamic aspect of recoil mechanisms is studied with simple one dimensional analysis as well as two dimensional numerical analysis. Method and procedure for experimental simulation is given. Full scale and reduced scale simulation is analyzed for its advantages and disadvantages. A new numerical scheme called 'finite differential' method is developed to solve the two dimensional unsteady NavierStokes equation. The new method utilizes the local analytical solution of the total problem. The solution of the problem is obtained by assembling the local analytic solution. The method is shown to be capable of solving flows with high Reynolds numbers
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Boundary layer CaliforniaSacramento River Dredging Embankments Floating bodies Fluid dynamics Frictional resistance (Hydrodynamics) Hydraulics Hydrodynamics Impact IowaCoralville Lake Laminar flowMathematical models Mississippi River Pumping stationsModels Sedimentation and deposition Sediment transport Ship models Ship resistance ShipsHydrodynamics ShipsHydrodynamicsMathematical models Turbulent boundary layerMathematical models Viscous flow Vortexmotion Wakes (Fluid dynamics) Water quality Water qualityMeasurement Water waves
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