HYDRONAUTICS INC LAUREL MD

Theory of High Speed Displacement Ships with Transom Sterns

SEP 1982

Authors: Marshall P. Tulin; C. C. Hsu; HYDRONAUTICS INC LAUREL MD

The full text of this report is not available and therefore is not for sale. This information is provided for reference purposes only.

A theory has been developed for high speed displacment ships. The theoretical treatment is based on treating the hull as finite in beam and draft but slender and the flow at the aft waterline being smooth and with a trailing wake. The trailing wake results in substantial residuary resistance at high speed for normal waterline shapes. Calculations are made for ships of highly variable parametric form and the results given. ...

Free Surface Flows without Waves

SEP 1982

Authors: Marshall P. Tulin; HYDRONAUTICS INC LAUREL MD

In this paper we explore, within the framework of first order theory, the existence of wave-free flows past submerged bodies in both two and three dimensions. This is done through consideration and mutual cancellation of the wave fields due to singularities and singularity distributions which can be interpreted in terms of body volume and vertical force distributions. The results may be of practical consequences for ship wave-making and also in ...

Prediction of Partial Cavitation on Marine Propellers

SEP 1982

Authors: P. N. Majumdar; HYDRONAUTICS INC LAUREL MD

The application of a theoretical method for predicting unsteady leading edge cavitation on two-dimensional foil sections with finite leading edge radii to the prediction of unsteady partial blade cavitation on marine propellers is discussed. The methods is used, together with the unsteady propeller lifting surface theory developed by Kerwin at MIT to predict partial leading cavitation on a propeller for which extensive model test data are available. It is concluded ...

Self Resonating Pulsed Water Jets for Aircraft Coating Removal: Feasibility Study

JUN 1982

90 pages

Authors: Georges L. Chahine; Virgil E. Johnson Jr.; Gary S. Frederick; HYDRONAUTICS INC LAUREL MD

The full text of this report is available for sale.

The objective of this project was to investigate the feasibility of disrupting a high pressure water jet into a discrete train of well organized slugs through passive acoustic self-excitation of the jet, and as a result to enhance the ability of the jet to remove aircraft coatings and to prepare surfaces for recoating. This innovative technique takes advantages of the water hammer pressures produced by the slugs' impact (which are ...

Technical Basis for Maneuvering Performance Standards

DEC 1981

Authors: R. A. Barr; E. R. Miller; V. Ankudinov; F. C. Lee; HYDRONAUTICS INC LAUREL MD

The development of a set of maneuvering performance standards applicable to ocean-going and Great Lakes ships larger than 1000 metric tons (deadweight) is described. These standards, which are considered suitable for immediate use for rating ship maneuvering performance, are based on relative performance (superior through marginal) of the majority of ships, rather an absolute (go/no go) rating. The ratings are based on available full scale (builder's trials) data for more ...

Experimental and Theoretical Investigation of Factors Affecting Fin-Body Interference

AUG 1980

Authors: Alex Goodman; HYDRONAUTICS INC LAUREL MD

A comprehensive series of wind-tunnel experiments were conducted to determine the static-lateral stability characteristics of a systematic series of submarine-type fin-body combinations. The effects of body-boundary layer and sidewash, fin-aspect ratio, fin-taper ratio, and diameter-span ratio on the total forces and moments of the fin-body combinations as well as on the fins in the presence of the bodies were evaluated. Measurements were also made to define the body boundary layer ...

The National Shipbuilding Reseearch Program. Proceedings of the REAPS Technical Symposium. Paper No. 11: HULSTRUX - A CASDAC Computer Aid for Hull Structural Contract Design

SEP 1979

20 pages

Authors: Stephen H. Klomparens; HYDRONAUTICS INC LAUREL MD

This paper is a status report on the development of a computer aided design tool for representing and displaying ship structure. Program Hull Structure (HULSTRX) is being developed for the Navy's (NAVSEA) Surface Ship Structures Branch as a part of the Navy's Computer Aided Design and Construction (CASDAC) project. HULSTRX will aid the Navy primarily during the contract design phase of ship design, which is referred to as level III ...

Removal of Explosives from Projectiles Using CAVIJET (Trade Name) Cavitating Fluid Jets.

AUG 1979

Authors: Andrew F. Conn ; Gary S. Frederick ; Han-Lieh Liu ; S. Lee Rudy ; Edward A. Krajkowski; HYDRONAUTICS INC LAUREL MD

The feasibility of using a CAVIJET cavitating fluid jet to remove high explosives from munitions has been examined. In tests with specimens of TNT and Composition B, no detonations occurred despite exposure at pressures well above anticipated operational values. From laboratory studies with an inert explosive simulant, the conceptual design for a pilot CAVIJET explosive removal facility has been established. These studies suggest that use of cavitating jets will provide ...

Towboat Maneuvering Simulator. Volume I. Users Guide

MAY 1979

Authors: Peter Van Dyke; HYDRONAUTICS INC LAUREL MD

The Towboat Maneuvering Simulator consists of a mathematical description of the hydrodynamic response of an integrated river tow embodied in a computer program running continuously on a computer, with a control console and other graphic and hard copy devices attached for input and output. It is thus a real time, interactive simulator, constantly responding to console commands and immediately updating the console displays. This volume describes the use of the ...

Towboat Maneuvering Simulator. Volume III. Theoretical Description.

MAY 1979

Authors: Eugene R. Miller Jr; HYDRONAUTICS INC LAUREL MD

The Towboat Maneuvering Simulator is based on the integration in time of the differential equations which describe the motions of the towboat and barge string in three degrees of freedom, i.e., yaw, sway and surge. This volume of the simulator documentation provides a description of the basic equations of motion included in the simulator and the relationships used to determine external forces and moments due to a bow thruster and ...

The Effects of Varying Ship Hull Proportions and Hull Materials on Hull Flexibility, Bending and Vibratory Stresses.

APR 1979

Authors: Pin Yu Chang; HYDRONAUTICS INC LAUREL MD

The effect of varying ship proportions and hull materials on hull flexibility and on the concomitant bending and vibratory stresses for an ore carrier, a tanker, containership, and a general cargo ship is evaluated. With the flexibility of the ship's hull represented by the natural frequency of the ship associated with the two-node shape, a potentially useful relation between the flexibility and bending moment has been established. An analysis indicates ...

Ship Wave Resistance - A Survey.

AUG 1978

Authors: Marshall P. Tulin; HYDRONAUTICS INC LAUREL MD

Studies of ship resistance have generated concepts and methods of importance for all of fluid mechanics; for example: the understanding of the origin of fluid resistance in its various components; model testing as a science; similitude laws in testing and analysis; group velocity in dispersive systems; asymptotic integration; and thin body theory. Here, developments including the earliest are surveyed and placed in some historical perspective. The development and current status ...

The Prediction of River Tow Maneuvering Performance.

MAY 1978

Authors: Eugene R. Miller Jr; HYDRONAUTICS INC LAUREL MD

A study was conducted to determine the feasibility of quantitatively predicting the maneuvering performance of river tows using hydrodynamic data from captive model tests and computer simulations. The effort included the formulation of the equations of motion for a river tow, a program of captive model tests and simulation studies of definitive and controlled maneuvers. The model tests were carried out with a large amplitude horizontal planar motion mechanism using ...

Measurements and Analysis of the Forces Acting on a Small Aircraft Flying in the Upwash of a Large Aircraft.

APR 1978

Authors: Clinton E. Brown; Peter Van Dyke; John W. Kloetzli; HYDRONAUTICS INC LAUREL MD

A study has been made of the forces and moments acting on a small aircraft while it is flying in the upwash field adjacent to and behind the wing tip of a larger airplane. Preliminary analysis of the expected ranges of forces and moments were made using available theoretical methods and confirming experiments were performed in the Hydronautics Ship Model Basin. The tests used a large model of the Boeing ...

On the Changes in Lift of Hydrofoils Due to Surface Injections of Polymer Additives

FEB 1978

132 pages

Authors: Abbas M. Sinnarwalla; T. R. Sundaram; HYDRONAUTICS INC LAUREL MD

Existing data on the effects on lift of symmetric hydrofoils due to the injection of polymer solutions on to their surfaces show that the lift can either decrease or increase depending on the polymer, injection velocity, location of injection, side of injection and angle of attack. A unified, albeit semiempirical, approach is suggested in the present report for correlating and explaining the apparently contradictory data. It is proposed that the ...

Evaluation of Deepwater Ports Mooring Load Monitoring and Prediction Systems.

FEB 1978

Authors: Roderick A. Barr; Sterling Tebay; Douglas Loeser; HYDRONAUTICS INC LAUREL MD

This report describes a study of mooring load monitoring and prediction systems for deepwater ports. The study considers both the complete systems and the various components of each system. The primary purpose of the study is to define and critically compare all candidate monitoring and prediction systems that might be used at a U.S. deepwater port and to recommend what, if any, systems should be required at such ports. The ...

The Development of a Hydroperm (Trademark) Microfiltration System for the Treatment of 'MUST' Hospital Wastewater Effluents.

OCT 1977

Authors: T. R. Sundaram; J. E. Santo; HYDRONAUTICS INC LAUREL MD

The results of a laboratory study to investigate the feasibility of utilizing Hydroperm filtration to treat the waste from the MUST hospital complex are presented. Hydroperm filtration utilizes rugged, thick-walled thermoplastic tubes of controlled microporosity to achieve almost total removal of suspended solids and significant removal of dissolved solids from waste streams even at relatively low filtration pressures (typically 5 psi or 0.35 kg/sq cm). A unique feature of the ...

The Development of a Hydroperm Microfiltration System for the Treatment of Domestic Wastewater Effluents.

JAN 1977

Authors: T. R. Sundaram; J. E. Santo; J. A. Brown; HYDRONAUTICS INC LAUREL MD

Laboratory experiments to investigate the feasibility of further concentrating the already concentrated (containing approximately one to two percent total solids) human wastes of the type encountered onboard U. S. Army watercraft or at field troop installations are described. The additional concentration is performed by cross-flow microfiltration utilizing unique microporous plastic tubes called HYDROPERM. It is shown that a significant degree of dewatering of the concentrate can be achieved while producing ...

Model Tests and Engineering Studies of the SWATH VII Small Waterplane Area Twin-Hull Ship.

NOV 1976

Authors: Karl L. Kirkman; B. J. Young; J. W. Kloetzli; P. Majumdar; HYDRONAUTICS INC LAUREL MD

The main objective of this effort is to obtain drag data and wake data for the SWATH VII Form, and using this data to obtain estimates of the required propulsive horsepower for the design displacement of 4355 metric tons. A secondary objective was to determine the stern pitch fin settings for minimum drag and, to do this, drag tests were performed for three speeds and a range of fin angles. ...

Lift and Drag Effects Due to Polymer Injections on the Surface of Symmetric Hydrofoils

OCT 1976

52 pages

Authors: Abbas M. Sinnarwalla; T. R. Sundaram; HYDRONAUTICS INC LAUREL MD

Experimental results are presented for the effects on the lift and drag on symmetrical hydrofoils due to the injection of dilute polymer solutions on to their surfaces. Results are presented for three different polymers, namely, Polyox, Polyacrylamide and Jaguar; for purposes of comparison, results are also presented for water injection. The results indicate that while, in general, polymer injection leads to a reduction in drag, the lift can either increase ...

Technical Practices Manual for Surface Ship Stack Design.

JUL 1976

145 pages

Authors: HYDRONAUTICS INC LAUREL MD

This manual contains a procedure for the design of stacks on U.S. Naval ships based upon the experience already gained by the Navy as well as commercial ship stack design practices. The techniques described in detail include design guidance for the height and shape of exhaust gas stacks, prediction of plume trajectories, estimation of downwind plume gas temperatures, and model testing techniques. The manual is divided into two parts. The ...

A Laboratory Study of Wind-Wave-Current Interaction. Part II.

JUN 1976

Authors: Richard S. Scotti; Garry W. Elliott; Mark S. Rice; HYDRONAUTICS INC LAUREL MD

This report studies the effect of wind and a spatially varying subsurface current field on both the wind-induced drift layer and the surface-wave spectrum. Steady state wind-wave-current interactions were established over a region of uniform current gradients which simulated an internal-wave-fixed measuring system. Wave-height spectra were recorded while wave-slope spectra were simultaneously made.

High Speed Computer Studies of Vortex Motions in Relation to Aircraft Wake Turbulence.

JAN 1976

Authors: Clinton E. Brown; Peter Van Dyke; HYDRONAUTICS INC LAUREL MD

Computations are presented and compared with experimental data from other sources for basic and advanced problems in aircraft - wake vortex interactions. Results are presented for coalescence of corotation and counterrotating vortex groups and finally a complete high speed computer method is developed for simulating the roll reaction of an aircraft to the wake produced by a large aircraft with flaps deployed. Suggestions for improved experimental approaches are also appended. ...

Evaluation of Current Towing Vessel Stability Criterion and Proposed Fishing Vessel Stability Criteria. Task 2. Tripping and Seakeeping Tests of Towing and Fishing Vessels.

JAN 1976

Authors: Michael G. Pepper; Eugene R. Miller; HYDRONAUTICS INC LAUREL MD

Results of a model test program, the second task of a three task study of stability criteria for towing and fishing vessels, are presented in this report. The tests covered both tripping and seakeeping of four models. The models were selected from a detailed study of fifty-one towing and fishing vessels carried out in Task One. A discussion of the testing methods and a limited analysis of the data are ...

Evaluation of Current Towing Vessel Stability Criterion and Proposed Fishing Vessel Stability Criteria. Task III.

JAN 1976

Authors: E. R. Miller; V. Ankudinov; HYDRONAUTICS INC LAUREL MD

This report presents the results of the third and last task in the study of intact stability criteria for towing and fishing vessels. This third task was the analysis, development, and evaluation of intact stability criteria based on the model testing and analysis work done under tasks one and two. Criteria are proposed for the following operating conditions: towing (self-tripping and tow-tripping modes of capsizing), where water on deck is ...

Evaluation of Current Towing Vessel Stability Criterion and Proposed Fishing Vessel Stability Criteria. Task II. Appendices A, B, C.

Jan 1976

Authors: Michael G Pepper; Eugene R Miller; HYDRONAUTICS INC LAUREL MD

Lift, Drag, and Pressure Distribution Effects Accompanying Drag-Reducing Polymer Injection on Two-Dimensional Hydrofoil

OCT 1975

53 pages

Authors: Daniel H. Fruman; Marshall P. Tulin; Han-Lieh Liu; HYDRONAUTICS INC LAUREL MD

Lift and drag forces and pressure distribution were measured for a 10 cm. chord, 20 percent relative thickness, NACA 63 sub 4-020, symmetrical, two-dimensional hydrofoil, with and without drag-reducing polymer injection. The 200 ppm solution of Polyox WSR 301 was introduced into the foil boundary layer with an injection velocity of 10 percent of the free stream velocity. The injection slits were situated at 10 and 30 percent of the ...

Development of Technical Practices for Selection of Roll Stabilization Systems. Phase II. Roll Tanks.

15 APR 1975

Authors: Roderick A. Barr; Vladimir Ankudinov; William C. Webster; HYDRONAUTICS INC LAUREL MD

This report discusses the selection and design of anti-roll or roll tank stabilization systems for naval ships, and methods for validating the predicted tank performance. Drafts of Brief Technical Practices Sheets for roll stabilization system selection and design at the preliminary and contract design levels are included.

Fast Current Oil Response System - Stage I, SVROS Development.

MAR 1975

Authors: W. T. Lindenmuth; A. M. Sinnerwalla; T. R. Sundaram; HYDRONAUTICS INC LAUREL MD

Combined theoretical and experimental studies show the effects of several parameters on the formation of a thickened pool of oil inside the Surface Velocity Retarder Oil Skimmer (SVROS), an energy absorbing device designed to recover thin oil slicks in high relative currents. This collection device is composed of an array of closely spaced flat plates that serve to gradually dissipate the kinetic energy of the oil/water inflow so that the ...

Evaluation of Current Towing Vessel Stability Criterion and Proposed Fishing Vessel Stability Criteria. Volume Two.

FEB 1975

Authors: E. R. Miller; G. C. Nickum; J. R. Rudnicki; B. J. Young; HYDRONAUTICS INC LAUREL MD

The results of the first, or formulation task, of a three task study of stability criteria for towing and fishing vessels are presented in this report. Included are a literature study, a fleet census and characterization, detailed stability calculations for 51 vessels, and the selection of models and test programs for task 2. Four models are selected and a proposed test program for towing vessel tripping and towing and fishing ...

Evaluation of Current Towing Vessel Stability Criterion and Proposed Fishing Vessel Stability Criteria. Volume One.

Feb 1975

Authors: E R Miller; G C Nickum; J R Rudnicki; B J Young; HYDRONAUTICS INC LAUREL MD

The results of the first, or formulation task, of a three-task study of stability criteria for towing and fishing vessels are presented in this report. Included are a literature study, a fleet census and characterization, detailed stability calculations for 51 vessels, and the selection of models and test programs for task 2. Four models are selected and a proposed test program for towing vessel tripping and towing, and fishing vessel ...

A Laboratory Study of Wind-Wave-Current Interactions. Part I.

JAN 1975

Authors: Richard S. Scotti; HYDRONAUTICS INC LAUREL MD

Two series of experiments were performed to study the interactions between both the wind-induced drift layer and the surface wave spectrum and a spatially varying subsurface current field. In the first, measurements were made of the response of the drift layer and surface wave spectrum to an appreciable, but unknown, current gradient. This was accomplished by forcing the current from a 90 cm-deep diffuser section onto a 68.7 cm-deep flat ...

Directional Slope and Curvature Distributions of Wind Waves

JAN 1975

45 pages

Authors: Jin Wu; HYDRONAUTICS INC LAUREL MD

The slope and curvature distributions of wind waves along two principal axes (upwind-downwind and crosswind) have been measured in a laboratory tank under various wind velocities. In both directions, the slope distributions are very closely Gaussian, and the components of the mean-square water-surface slope vary logarithmically with the friction velocity of the wind. As the wind velocity increases, the ratio between these two components increases and falls between 0.5 and ...

The Pressure Field of a Vortex Wake in Ground Effect,

1975

Authors: Clinton E. Brown; HYDRONAUTICS INC LAUREL MD

The ground pressures under a descending pair of vortices, such as might be generated by aircraft either landing or taking off are computed. It is found that as the vortices first approach the ground, only positive pressures are produced; however as the descent continues the high velocity field of the vortices makes itself apparent in dips to sub-atmospheric pressure which lie closely beneath the vortex center. Nevertheless, a substantial positive ...

EFFECTS OF FATIGUE AND DYNAMIC RECOVERY ON RAIN EROSION

DEC 74

Authors: A. F. Conn; S. L. Rudy; HYDRONAUTICS INC LAUREL MD

Surface Effects an Analysis and Review of the Processes Involved and Phenomena Observed

DEC 1974

100 pages

Authors: O. M. Phillips; HYDRONAUTICS INC LAUREL MD

This report analyzes and reviews the processes involved in the generation of modulations in short wave structure by internal waves. The emphasis is on field conditions where, in general, there is wind blowing, a mean current with vertical structure, long and short waves at different directions to the internal wave and possibly surface films. The applicability or otherwise of theoretical analyses and laboratory experiments to field situations is discussed, the ...

Development of a Technical Practice for Roll Stabilization System Selection. Phase I.

OCT 1974

Authors: Eugene R. Miller; John J. Slager; William C. Webster; HYDRONAUTICS INC LAUREL MD

The determination of required roll motion performance or maximum permissible ship rolling, for a given application, is considered. The influence of human effectiveness and subsystem performance on this determination is discussed. Methods are given for the evaluation of and selection of the best type or types of roll stabilization systems for a given ship. Means are provided for assessing the size and weight of various roll stabilization devices including active ...

Bollard Thrust Predictions, Based on Model Tests, for the 300 Ton Cargo Transporter Barge Design.

SEP 1974

Authors: J. J. Slager; G. W. Peters; J. G. Rudnicki; B. J. Young; HYDRONAUTICS INC LAUREL MD

As part of the continuing development of the 300 Ton Cargo Transporter Barge design, additional model tests were carried out to provide data for predictions of the Barge astern, astern quartering, and athwartships bollard thrust performance. The predicted bollard thrust performance, for thrust directed in the athwartships direction, is somewhat less than was assumed during the Barge preliminary design phase; however, it is shown that the Barge bollard thrust performance ...

Effect of Drag-Reducing Polymer Injection on the Lift and Drag of a Two- Dimensional Hydrofoil

SEP 1974

37 pages

Authors: D. H. Fruman; T. R. Sundaram; S. J. Daugard; HYDRONAUTICS INC LAUREL MD

The present paper describes an experimental investigation on the effects of injecting drag-reducing polymer solutions into the turbulent boundary layer of two NACA 63, two-dimensional, symmetrical, hydrofoils. The experiments were performed in a high-speed circulating channel with free stream velocities of up to 13 m/sec. The two foils used were 10 and 20 cm in chord, though both had a maximum thickness of 2 cm. The incidence of the foils ...

Simulation of Wake Vortices Descending in a Stably Stratified Atmosphere.

JUL 1974

Authors: Clinton E. Brown; Karl Kirkman; HYDRONAUTICS INC LAUREL MD

An experimental water tank simulation of aircraft wake vortices descending in a stable atmosphere has indicated that the atmospheric stability stops the downward movement and in some cases produces a subsequent rebound. The tests were carried out in a large ship model basin using a rectangular planform wing. Lift coefficients were selected, and stable atmospheric conditions were obtained by temperature (density) stratification of the towing basin. The model parameters and ...

Development of a Novel High Velocity Oil Slick Skimmer.

JUN 1974

Authors: William T. Lindenmuth; HYDRONAUTICS INC LAUREL MD

Experimental investigations show that thin slicks of oil can be recovered in currents of up to 10 fps with a new Surface Velocity Retarder Oil Skimmer (SVROS). This collection device is composed of an array of closely spaced flat plates. The plates serve to gradually dissipate the kinetic energy of the oil/water inflow so that oil can be collected at high relative velocities without the entrainment losses typical of all ...

The Strain Rate Dependence of Three High Strength Naval Alloys.

JUN 1974

Authors: Andrew F. Conn; S. Lee Rudy; Stephen C. Howard; HYDRONAUTICS INC LAUREL MD

The properties of three alloys were studied: a Type HY-80 steel, a Type HY-130 steel, and a titanium alloy: Ti-6211. (6Al 1Nb 0.8Mo 1Ta). These materials were subjected to a wide range of uniaxial tensile rates of straining at room temperature: static tests, rapid loading tests, and dynamic tests. The results of these tests are replotted to demonstrate the dependence of stress as a function of rate of straining. It ...

Evaluation of Pump Emulsification Characteristics.

FEB 1974

Authors: Daniel H. Fruman; T. R. Sundaram; HYDRONAUTICS INC LAUREL MD

The study examines the emulsification characteristics of two 10 gpm pumps (a rotary vane, positive displacement pump and a centrifugal pump) under various conditions of oil feed and discharge pressures. A limited parametric investigation of emulsion formation under controlled ultrasonic energy inputs was also carried out to complement the results obtained from the pump emulsification tests. (Author)

FLEXURAL FATIGUE AND CAVITATION EROSION OF GLASS REINFORCED PLASTIC COMPONENTS.

JAN 74

Authors: A. F. Conn; S. L. Rudy; S. C. Howard; HYDRONAUTICS INC LAUREL MD

Flexural fatigue tests were conducted on ten types of glass fiber re- inforced plastic composites in synthetic sea water. A new fatigue facility was developed and is described. A limited series of vibrator cavitation erosion testing was also performed on several of the compos-ites. The object was to determine the effects of various parameters on the ability of the material to resist corrosion fatigue failure and cavitation damage, ranking these ...

Handbook of Cavitation Erosion.

JAN 1974

Authors: A. Thiruvengadam; HYDRONAUTICS INC LAUREL MD

This revised Handbook is a completely rewritten and updated version of the original 6Handbook of Cavitation Damage6 which was published under the auspices of the Office of Naval Research in 1965. This new edition contains the very latest information pertaining to scal-ing and the effects of fluid properties on Cavitation Erosion, as well as new field experiences with some of the Navy's high perfor-mance ships. Again, the scope of this ...

The Influence of the Chemical Nature of Polymers on Their Drag Reduction Characteristics.

JAN 1974

Authors: M. A. Frommer; A. Lavy; M. A. Kraus; Daniel H. Fruman; John E. Santo; HYDRONAUTICS INC LAUREL MD

The influence of the chemical nature of polymers on their drag reduction characteristics was investigated for four different compounds, two commercially available Polyacrylamide (PAM) Polystyrene sulfonate (PSS) and two laboratory modifications of PAM. The degradation of these polymers under repeated shear was also investigated It is concluded that, by properly tailoring the structural changes of the polymer molecules, higher drag reductions with less degradation can be obtained. Finally, the results ...

Concept Design and Cost Analysis of Restricted Draft Dry Bulk Carriers.

NOV 1973

Authors: Donald P. Roseman; Geoffrey W. Peters; Horton W. Lain; HYDRONAUTICS INC LAUREL MD

The development of restructed draft dry bulk carriers is recognized as a means for reducing transportation costs by permitting the operation of larger vessels out of existing ports. For three given drafts, a parametric computer design study of deadweight capacity and corresponding dimensions and form characteristics is carried out to determine maximum feasible deadweight, subject to assumed physical boundary conditions and economic considerations. Restricted draft ship characteristics selected for the ...

Correlation of Micro- and Macroscopic Structures of Wind Waves and Differential Roughening and Smoothing of Surface Waves by Wind

NOV 1973

43 pages

Authors: Jin Wu; HYDRONAUTICS INC LAUREL MD

Simultaneous measurements were conducted in a wind-wave tank of the ripple slopes with an optical instrument and of the carrier-wave profiles with a wave-height gage. The experiments were conducted under various wind CONDITIONS: either steady or unsteady wind blowing over pre-existing regular surface waves. The data were analyzed to determine the slope distributions of ripples located on various portions of the carrier-wave profiles under steady wind, and the differential roughening ...

Wavemaking by a Thin Ship: Second Order Nonlinear Effects

OCT 1973

52 pages

Authors: Gedeon Dagan; HYDRONAUTICS INC LAUREL MD

The reporting investigates second order terms of the expansion in the beam/length ratio of the potential of flow past a thin ship. The ship is in a steady translational motion, in water of infinite depth and infinite lateral extent, within its central plane of symmetry. Heave and trim are not taken into account.

Microscopic Structure of Disturbed Water Surface under Fluctuating Winds.

OCT 1973

Authors: Jin Wu; HYDRONAUTICS INC LAUREL MD

Slope and curvature distributions of the disturbed water surface under, and shear velocities of, fluctuating winds were measured. The results obtained with the same average wind velocity but with fluctuations of various frequencies and amplitudes are compared. The fluctuations are found to be critical on wing and wave structures, when the regime of the wind boundary layer is affected. The influence of fluctuations becomes secondary, when the wind boundary layer ...