| Development of a Four-Fin Bio-Inspired UUV: CFD Studies |
04 Sep 2012 |
39 pages |
| Authors:
Ravi Ramamurti; Jason D Geder; NAVAL RESEARCH LAB WASHINGTON DC LAB FOR COMPUTATIONAL PHYSICS AND FLUID DYNAMICS
|
 | The development of an unmanned underwater vehicle (UUV) with four actively controlled curvature flapping fins is described. Three dimensional unsteady flow computations past several configurations of the vehicle are computed and based on the minimum drag a nearly elliptical cross-section with a smooth leading and trailing sections was obtained. The hydrodynamic characteristics of this vehicle at NRL are computed for a range of operational conditions and a dynamic mode of ... |
|
| Incorporation of a Nearshore Hydrodynamic Model into the Unmanned Cooperative Cueing and Intervention Automated Planner |
30 Sep 2011 |
4 pages |
| Authors:
James M Kaihatu; TEXAS A AND M UNIV COLLEGE STATION DEPT OF CIVIL ENGINEERING
|
| The overall goal for this project is to incorporate the Delft3D hydrodynamic model suite into the Unmanned Cooperative Cueing and Intervention Automated Planner (UCCI). This would allow the UUV system to incorporate real-time information into its routing, and also allow for possible feedback between the modeling system and the UUV system. |
|
| Hydrodynamic Design Optimization Tool |
Aug 2011 |
32 pages |
| Authors:
Chi Yang; Devin Bowers; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| A rapid ship hull form generation tool is developed in support of an ongoing ONR research project on the development of a methodology for innovative hydrodynamic design of ship hull forms. The hull lines/curves in this tool are described by various orders of polynomials and the polynomials are determined using hull form parameters. The hull generation tool is implemented using Matlab to enable graphic user interface. Two hull forms are ... |
|
| Flow Characteristics and Status of CFD Hydrodynamic Model Development in Sudden Contraction Manifold/Orifice Configurations |
Jul 2011 |
85 pages |
| Authors:
W H Nurick; NURICK AND ASSOCIATES CAMARILLO CA
|
| Applications of sudden contraction manifold/orifice configurations range from city water drainage, diesel and gasoline fuel injection systems, and high speed underwater torpedoes, as well as rocket engine injector manifold flow passages. While the literature is extensive and dates back more than a century, the details of the flow characteristics as well as the quantitative impacts on losses are still sketchy at best. A clear understanding of the detailed process flow ... |
|
| Dynamics and Control of Non-Smooth Systems with Applications to Supercavitating Vehicles |
Jan 2011 |
208 pages |
| Authors:
Vincent Nguyen; MARYLAND UNIV COLLEGE PARK DEPT OF COMPUTER SCIENCE
|
| The subject matter of this dissertation relates to the dynamics of non-smooth vehicle systems, and in particular, supercavitating vehicles. These high-speed underwater vehicles are designed to have sustained vaporous or ventilated gas cavities that form over the entire vehicle. In terms of the modeling, the system non-smoothness is caused by the interaction forces generated when the vehicle contacts the cavity. These planing interactions can cause stable and unstable dynamics, some ... |
|
| CFD Analysis of a Penta-hulled, Air-Entrapment, High-Speed Planning Vessel |
01-Mar-2008 |
211 pages |
| Authors:
Edward R Fultz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The objective of this thesis is to analyze the hydrodynamic properties of a specialized penta-hulled, air entrapment, high-speed planning vessel. Due to the unique features of this hull, a multi-layered approach based on computational fluid dynamics was adopted. The first is a steady state model with no free surface effects. It determines the lift and drag on the hull at a fixed waterline. It does not capture any of the ... |
|
| Reliability-Based Performance Assessment of Damaged Ships |
OCT 2006 |
223 pages |
| Authors:
Y. W. Lee; Y. Pu; H. S. Chan; A. Incecik; R. S. Dow; I. Khan; P. K. Das; P. E. Hess; NEWCASTLE-UPON-TYNE UNIV (UNITED KINGDOM)
|
| The objective of this research is to develop a reliability-based procedure for the ship operators to make the immediate repair actions by evaluating the effects of the damage on the safety of the ship using residual strength assessment procedure. In this study, a procedure has been developed to assess structural integrity of damaged ships. The procedure consists of four steps: (1) Identify the location and size of the openings; (2) ... |
|
| Evaluation of Skin-Spar Joint Resistance to Hydrodynamic RAM |
MAR 2006 |
357 pages |
| Authors:
Greg Czarneck; Michele Maxson; J. Sawdy; M. Miller; R. Hinrichsen; TEST WING (46TH) WRIGHT-PATTERSON AFB OH AEROSPACE SURVIVABILITY AND SAFETY FLIGHT DIVISION
|
| This paper presents the application of a new dynamic joint loading methodology that uses a RamGun device. Projectile-induced hydrodynamic ram can generate fuel-tank pressures in excess of 10,000 psi. This event is potentially catastrophic for aircraft fuel tanks designed to survive sustained pressures of little more than 50 psi. While the magnitude of ram pressure is dictated by a combination of fuel-level and projectile threat, skin-spar joint design is the ... |
|
| Waves, Currents, and Sediment Transport in the Surf Zone Along Long, Straight Beaches |
AUG 2005 |
308 pages |
| Authors:
Yoshimitsu Tajima; Ole S. Madsen; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CIVIL ENGINEERING
|
| This study presents a theoretical model for predictions of nearshore hydrodynamic characteristics and the local sediment transport rate along long, straight beaches. The wave may be periodic or random, the beach may be plane or barred, and the bed may be concrete or covered with movable natural sand grains. The present model must be efficient and flexible so that it can accommodate iterative computations for time-varying and, hence, arbitrary beach ... |
|
| Sensibility Study of St Andrew Bay Rapid Response System for Naval Applications |
JUN 2005 |
115 pages |
| Authors:
Patrice Pauly; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Rapid assessment of littoral ocean physical and chemical conditions has represented a great challenge in recent years. For the physical part, time constraint may limit to using the barotropic mode. But because rain can be significant in St Andrew Bay system, Florida, fresh water, even when rivers lack, is a prevailing salinity regulator through ground seepage. Therefore, studying the baroclinicity and forcing mechanisms should provide a reasonable guidance help for ... |
|
| US-Japan Cooperative Research on Biology-Inspired Precision Maneuvering of Underwater Vehicles |
02 JUN 2004 |
4 pages |
| Authors:
Naomi Kato; OSAKA UNIV (JAPAN) DEPT OF NAVAL ARCHITECTURE AND OCEAN ENGINEERING
|
| The objective of this project was to numerically and experimentally evaluate the underwater precision maneuverability of a cylindrical body, in particular the STOP & HOVER motions, by using fore and aft pairs of pectoral fins, similar to their usage in a fish. We examined the hydrodynamic characteristics of a mechanical pectoral fin through experimental and numerical analyses and the optimal match of the fin motions to generate the maximum hydrodynamic ... |
|
| Program Documentation for the Channel Analysis and Design Evaluation Tool (CADET) |
MAY 2004 |
73 pages |
| Authors:
Paul J. Kopp; Andrew L. Silver; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| The Naval Surface Warfare Center, Carderock Division has developed a software tool, the Channel Analysis and Design Evaluation Tool (CADET), to aid in determining the operational depth of an entrance channel to commercial ports. CADET is a set of computer programs that use probabilistic risk analysis techniques to evaluate the accessibility of a series of channel depths for multiple vessel geometries and loading conditions. The operational depth is governed by ... |
|
| Underwater Weapon System Having a Rotatable Gun |
08 DEC 2003 |
14 pages |
| Authors:
Thomas J. Gieseke; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This patent application discloses an underwater weapon system having a rotating gun system mounted in a vehicle housing. The gun system includes a gun and ammunition sealed within a waterproof housing with the gun muzzle protruding from the housing. The gun system is rotatable relative to the first and second halves of the housing, while the housing can be maneuvered to rotate through a plane of rotation of the gun ... |
|
| Development and Validation of a Stochastic Model for the Hydrodynamic Forcing Function from Submarine Propulsors and Appendages |
23 JAN 2002 |
17 pages |
| Authors:
Leonard J. Peltier; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
|
| The long-term objective of this research was to develop a stochastic model for the two-point surface-pressure correlation and the related surface- pressure spectrum that uses RANS data as input. The model would have given a complete hydrodynamic forcing function for structural acoustics applications. The use of Reynolds-Averaged Navier-Stokes data as input to the model allowed the model to respond to local flow and configuration complications through the RANS modeling. Contemporary ... |
|
| Review of Theoretical Approaches to Nonlinear Supercavitating Flows |
FEB 2001 |
31 pages |
| Authors:
G. M. Fridman; A. S. Achkinadze; SAINT PETERSBURG STATE MARINE TECHNICALUNIV (RUSSIA) SHIP THEORY DEPARTMENT
|
| The purpose of the paper is to present a brief review of basic theoretical approaches to two-dimensional (2D) nonlinear supercavitating flows in the framework of theory of jets in an ideal fluid. In this connection discussed are Kirchhoff and Zhukovsky methods, Chaplygin method of 'singular points', method of integral equation, etc. A simple model problem of a supercavitating (SC) flat plate at zero cavitation number sigma = 0 is chosen ... |
|
| Control of Supercavitation Flow and Stability of Supercavitating Motion of Bodies |
FEB 2001 |
29 pages |
| Authors:
Yu. N. Savchenko; UKRAINIAN ACADEMY OF SCIENCES KIEV INST OF HYDROMECHANICS
|
| Control of the supercavity parameters is necessary for maintenance of calculated regime of the supercavitation flow in unsteady conditions: at changing the velocity and depth of the body motion. The problem of cavitation flow control includes the two problems connected among themselves: I)the control of cavity dimensions; II) the control of forces on a cavitating body. We consider sequentially both problems. |
|
| Characterization of U.S. Army Corps of Engineers Reservoirs: Design and Operational Considerations |
DEC 2000 |
11 pages |
| Authors:
Robert Kennedy; Joan Clarke; William Boyd; Tom Cole; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS ENVIRONMENTAL LAB
|
| This technical note describes design and operational characteristics of U. S. Army Corps of Engineers (CE) reservoirs as they relate to potential management opportunities through operational change. The reported data serve to identify groups of reservoirs based on their physical and operational characteristics. Subsequent efforts will employ the water quality model CEQUAL- W2 to assess potential benefits due to operational changes. |
|
| USCGC HEALY (WAGB 20) Results of Performance and Special Trials |
SEP 2000 |
83 pages |
| Authors:
George H. Brodie; Lowry L. Hundley; Steven C. Intolubbe; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| Performance and Special Trials consisting of standardization, fuel performance, tactical, and maneuvering trials were conducted on USCGC HEALY (WAGB 20) during builder's sea trials to evaluate the hydrodynamic performance of the ship, The trials were conducted in the Gulf of Mexico off the coast of Louisiana from 23 through 31 August 1999. Standardization and fuel performance trials results showed that HEALY achieved the maximum powering ... |
|
| RANS Analysis of Free-Surface and Bottom Effects on Axisymmetric RCMS |
MAR 2000 |
28 pages |
| Authors:
Henry J. Haussling; Roderick M. Coleman; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| The UNCLE Reynolds-averaged Navier-Stokes code is used to investigate free-surface and bottom effects on an axisymmetric radio-controlled submarine model. It is shown that the basin bottom and water surface have small but noticeable influences on the hydrodynamic vertical force and pitching moment on the body for typical depths of submergence. The influence of submergence depth and speed on the forces and moments is analyzed. It is ... |
|
| Results of Experiments With a Segmented Model to Investigate the Distribution of the Hydrodynamic Forces and Moments on a Streamlined Body of Revolution at an Angle of Attack or With a Pit |
FEB 2000 |
49 pages |
| Authors:
Eric F. Van Randwijck; Jerome P. Feldman; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| The hydrodynamic forces and moments which are developed on unappended streamlined bodies of revolution at small and large angles of attack or with a pitching angular velocity were investigated by captive-model experiments and by theory. The captive-model experiments were performed with a segmented model of a Series 58 body in the deep water basin of the David Taylor Model Basin and on the rotating arm. Exact and ... |
|
| A Methodology for Design of Passive Isolation for Ship/Barge Connection |
SEP 1999 |
122 pages |
| Authors:
Scott R. Barry; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Current ramp designs used in RORO operations have been determined to be structurally inadequate in Sea-State 3. The main reason for this is that when the ramp is loaded with two vehicles, the relative motions between the ship and the discharge facility induce stresses above yield. The objective of this thesis is to formulate the problem and present results that will enable the design of proper isolators. ... |
|
| Review of Dolphin Hydrodynamics and Swimming Performance |
AUG 1999 |
187 pages |
| Authors:
F. E. Fish; J. J. Rohr; SPACE AND NAVAL WARFARE SYSTEMS COMMANDSAN DIEGO CA
|
| The principal objective of this project was to preform a comprehensive review of performance, kinematics, and swimming hydrodynamics by dolphins and other cetaceans. This report describes information obtained from the available literature including published research and technical reports from English-speaking and Russian sources. The project team specifically studied routine and maximum swimming speeds, morphological design related to hydrodynamic performance, drag reduction, swimming kinematics, thrust production and efficiency, behavior strategies employed ... |
|
| Measurement of Transient Flow Induced by a Berthing barge |
MAR 1998 |
44 pages |
| Authors:
E. T. Huang; D. A. Davis; C. H. Kim; H. C. Chen; NAVAL FACILITIES ENGINEERING SERVICE CENTER PORT HUENEME CA
|
| The Navy is developing a numerical solution that uses the Chimera RANS/free-surface technique to address the critical features of transient flow around a berthing ship. Experimental data required to validate the ship berthing model were collected during scale model tests conducted at a shallow water model basin. The test setup included a towing carriage traveling on rail guides used to power a scale model barge toward the ... |
|
| Real-Time Modeling of Cross-Body Flow for Torpedo Tube Recovery of the Phoenix Autonomous Underwater Vehicle (AUV) |
MAR 1998 |
227 pages |
| Authors:
Kevin Michael Byrne; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A virtual world provides an exceptional resource for the testing and development of an Autonomous Underwater Vehicle (AUV). The difficulties associated with the underwater environment are numerous and complex. In order to properly verify vehicle results in the laboratory such a world must accurately model the physics associated with the vehicle, its submerged hydrodynamics characteristics, and interactions with the environment. Environmental effects such as wave motion, currents, and flow forces ... |
|
| Maximizing AUV Slow Speed Performance |
SEP 1997 |
|
| Authors:
Phillip J. LeBas; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF APPLIED OCEAN PHYSICS AND ENGINEERING
|
 | A review of the Odyssey IIb autonomous underwater vehicle shows that energy costs associated with vehicle controls can be reduced and operational flexibility improved with relatively simple, low cost improvements. Because the operating speed that minimizes forward drag is not necessarily the same as that required for optimum sensor performance, a variable speed capability extending to the bottom of the vehicle speed range is sought. Optimizing Odyssey IIb AUV performance ... |
|
| Parametric Prediction of the Transverse Dynamic Stability of Ships |
SEP 1997 |
79 pages |
| Authors:
James W. Sebastian; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| There currently exists no direct method for predicting the righting energy of a ship based on key geometric hull properties. Consequently, naval architects traditionally select hull parameters based on other constraints and merely check the dynamic stability indicators after designing the preliminary body plan. Quantifying these relationships would allow such indicators to be used as design variables in optimizing a hull form. Additionally, the hull form has a considerable impact ... |
|
| Validation of SHIPMO7 and PRECAL with the CPF Hydroelastic Model |
AUG 97 |
|
| Authors:
Kevin A. McTaggart; Dann L. Chow; DEFENCE RESEARCH ESTABLISHMENT ATLANTICDARTMOUTH (NOVA SCOTIA)
|
| This report gives results of an extensive validation of DND's strip theory program SHIPMO7 and the three-dimensional ship motion code PRECAL developed by Cooperative Research Ships. Ship motion and sea load predictions are compared with results for the CPF hydroelastic model, which was tested in regular and irregular waves in both head and oblique seas. In general, both codes give excellent agreement for ship motions and reasonable agreement for sea ... |
|
| A Numerical Study of Fluid Flow Around Two-Dimensional Lifting Surfaces |
JUN 97 |
167 pages |
| Authors:
John D. Dannecker; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING
|
| There are always differences between theoretical and experimental results in the study of lifting surfaces. Bounding box control volume measurements infrequently yield exact conservation of mass or consistent values for lift and drag coefficients. Numerically calculated wakes often differ from experimental data. Quite often, an empirical correction can be applied to fit theory to experiment to account for these differences. However, as the demands for state of the art foil ... |
|
| Conceptual Study of Articulated Stable Ocean Platform. Part 1 |
06 MAY 97 |
119 pages |
| Authors:
Trevor R. Mills; Zhihuang Ran; MCDERMOTT ENGINEERING HOUSTON LLC TX
|
| A conceptual study has been completed to evaluate the feasibility of a new concept of a floating storage platform - the Articulated Stable Ocean Platform (ASOP). The unique aspects of the ASOP is the articulation of the stabilize buoys which were introduced for the purposes of reducing wave load and overall vessel motion. The ASOP was designed to have a fuel storage capability of 1 million barrels and to support ... |
|
| Conceptual Study of Articulated Stable Ocean Platform. Part 2. Volume 1 |
06 MAY 97 |
320 pages |
| Authors:
Trevor R. Mills; Zhihuang Ran; MCDERMOTT ENGINEERING HOUSTON LLC TX
|
| A conceptual study has been completed to evaluate the feasibility of a new concept of a floating storage platform - the Articulated Stable Ocean Platform (ASOP). The unique aspects of the ASOP is the articulation of the stabilize buoys which were introduced for the purposes of reducing wave load and overall vessel motion. The ASOP was designed to have a fuel storage capability of 1 million barrels and to support ... |
|
| Body Forces for an FF1052 Propeller |
MAY 97 |
21 pages |
| Authors:
Caroll L. Tseng; Phuc Nguyen; Donald Fuhs; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECT ORATE
|
| This project is the beginning of an effort to develop a general method for computing the effect of the propeller on the flow around the stern of surface ships, by treating the propeller as a body force when using a Reynolds Averaged Navier Stokes (RANS) code to compute the hull flow. The body force is a time average value that varies in the circumferential and radial directions across the propeller ... |
|
| The Study of Fluid-Elastic Solid Interaction Phenomena using Finite Element Strategies |
28 MAR 97 |
6 pages |
| Authors:
Steve Ray; Gloria Wren; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| One of the goals of the Weapons and Materials Research Directorate of the US Army Research Laboratory (ARL) is to develop propulsion technologies for future gun systems. This effort requires continued improvement of current guns which are already quite close to optimal, and the use of novel, high energy propellants and designs in future weapons. These new designs and propellants make use of next-generation concepts which are not yet well ... |
|
| Nonlinear Analysis of Coupled Roll/Sway/Yaw Stability Characteristics of Submersible Vehicles |
MAR 1997 |
84 pages |
| Authors:
Sotirios E. Tsamilis; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The problem of coupled roll, sway, and yaw stability analysis of submersible vehicles is analyzed, with particular emphasis on nonlinear studies. Previous results had indicated that a primary loss of stability is through the development of limit cycles. This loss of stability is due to the coupling of roll into sway and yaw and cannot be predicted by considering the uncoupled dynamics. In this study, it is shown that the ... |
|
| Smart Structures and Materials 1997. Passive Damping and Isolation. Volume 3045 |
MAR 97 |
350 pages |
| Authors:
L. P. Davis; SPIE-THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING BELLINGHAM WA
|
| PARTIAL CONTENTS OF THIS PROCEEDINGS INCLUDE: (1) PARTICLE AND HYSTERETIC DAMPING; (2) LAUNCH VIBRATION ISOLATION; (3) EMBEDDED PIEZO AND ACTIVE CLD; (4) ELECTRORHEOLOGICAL FLUID (ERF) DAMPING; (5) PASSIVE CONSTRAINED LAYER DAMPING (CLD); (6) CHARACTERIZATION OF DAMPING MATERIALS; (7) SYSTEM APPLICATIONS OF PASSIVE DAMPING AND ISOLATION; (8) ACTIVE CLD. |
|
| Kilo-Constant-Current Anemometer System for Surface Hot-Films in Water |
17 FEB 97 |
78 pages |
| Authors:
Todd G. Wetzel; Roger L. Simpson; Jonathan L. Fleming; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE AND OCE AN ENGINEERING
|
| A system for measuring the 3-D separation topology as a large scale underwater submarine model is described. Magnitude-only hot-film sensors are powered by constant current anemometers. The system is designed to use over 1000 sensors. Minima in skin friction magnitude are used to indicate crossflow separation. The hardware and sensor installation is described along with the result of several tests at the David Taylor Research Center's Rotating Arm facility. Future ... |
|
| A Combined High-Order Spectral and Boundary Integral Equation Method for Modelling Wave Interactions With Submerged Bodies |
FEB 97 |
|
| Authors:
Gregory R. Thomas; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF OCEAN ENGINEERING
|
| The interaction of submerged maneuvering vehicles with the free surface is a topic of importance in ocean engineering. Present methods for estimating the forces and motions due to wave-body interactions are limited in their ability to efficiently compute forces and motions of interest when free surface slopes are steep or body motions are large. Methods are required which contribute to overcoming these difficulties. This thesis presents a method for analyzing ... |
|
| Added Resistance Prediction in SHIPMO7 Using a Near-Field Method |
JAN 1997 |
|
| Authors:
Kevin A. McTaggart; DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)
|
| This technical memorandum discusses the implementation of a near- field method for prediction of added resistance in the Strip theory program SHIPMO7. Comparisons with experimental data for Series 60 hull forms and a frigate indicate accuracy similar to other methods, including three-dimensional codes. Advantages of the current method include computational efficiency, robustness, and reasonable values for added resistance in following seas. Inclusion of the SHIPMO7 dynamic swell-up option improves accuracy ... |
|
| Point Loma Reballast Stability Study |
JAN 97 |
119 pages |
| Authors:
Michael A. Miner; OREGON STATE UNIV CORVALLIS
|
| Large scale model studies of the Point Loma sewer outfall (San Diego, California) were performed at the O. H. Hinsdale Wave Research Laboratory, Oregon State University, in order to determine the stability of a proposed armor mound structure. Two scale models were constructed, one at 1:24 scale and one at 1:33.6. The 1:24 scale model was tested at Froude scaling of 1:24, 1:28.8, and 1:33.6 to examine median prototype armor ... |
|
| Validation of SHIPMO7 and PRECAL with a Warship Model |
NOV 96 |
|
| Authors:
Dann L. Chow; Kevin A. McTaggart; DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)
|
| This technical memorandum describes a validation study of SHIPMO7 and PRECAL, two frequency domain codes for predicting ship motions and sea loads in waves. SHIPMO7 is a strip theory code while PRECAL is a three-dimensional panel code. Results from the two codes are compared with non-proprietary experimental data for a warship model. In general, SHIPMO7 gives good agreement with motions and sea loads, while PRECAL is slightly inferior. The consistently ... |
|
| Proposed Method for Calculation of Spectral Response to Random Wave Loading Using Top-Down Finite Element Modelling |
NOV 96 |
|
| Authors:
David C. Stredulinsky; DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)
|
| Ship structural design and analysis is moving away from empirical static design wave balance and towards more rational methods involving computer modeling of the sea load and structural response. A ship load history is usually only known or predicted in terms of an operational profile defined by the time spent in many combinations of different ship speeds, headings and sea environments. Each combination of speed, heading the wave frequency spectrum ... |
|
| Mathematical Model for MANSIM Version 2: A Surface Ship Maneuvering, Stationkeeping, and Seakeeping Simulator Computer Program |
OCT 96 |
33 pages |
| Authors:
Paul J. Kopp; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECT ORATE
|
| This report documents the mathematical model of a combined maneuvering, stationkeeping, and seakeeping simulation computer program for two different classes of mine hunting vessels. The model features a mix of physical based models for the propulsion systems and control surfaces and hydrodynamic coefficient based hull model. The approach follows the concept of the modular maneuvering model. A quasi-steady assumption is utilized for the seakeeping motion effects. This allows the calm ... |
|
| Dualcavitating Hydrofoil Structures. |
03 SEP 1996 |
|
| Authors:
Young T. Shen; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The invention is directed to hydrofoil structures for efficient operation over a wide speed range from subcavitating to supercavitating operation. A dualcavitating hydrofoil is provided that overcomes cavitation problems associated with high speed operation of prior art subcavitating hydrofoil structures by providing a supercavitating profile shape in the lower surface to achieve a supercavitating condition at high speeds and that overcomes problems associated with low speed operation of prior art ... |
|
| Underwater Vehicle and Combination Directional Control and Cable Interconnect Device. |
03 SEP 1996 |
|
| Authors:
Jeffrey L. Cipolla; Ronald E. Waclawik; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| There is presented an assembly comprising an underwater vehicle and a combination directional control and cable interconnect device therefor. The underwater vehicle remains underwater during travel of the vehicle through water. The directional control and cable interconnect device comprises a single arm extendible from one side of the underwater of vehicle. The arm includes a multiplicity of fins in a compact array for contact with the water through which the ... |
|
| Studies on Submarine Control for Periscope Depth Operations |
SEP 96 |
156 pages |
| Authors:
John V. Tolliver; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Requirements for submarine periscope depth operations have been increased by integration with carrier battle groups, littoral operations, and contributions to joint surveillance. Improved periscope depth performance is therefore imperative. Submarine control personnel rely on a large number of analog gauges and indications. An integrated digital display system could enhance the ergonomics of the human control interface and display additional parameters. This thesis investigates the required feedbacks for robust automatic depth ... |
|
| Application of an Upwind High Resolution Finite-Differencing Scheme and Multigrid Method in Steady-State Incompressible Flow Simulations |
JUN 96 |
36 pages |
| Authors:
Cheng I. Yang; Yanhu Guo; C. H. Liu; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECT ORATE
|
| The analysis and design of a submarine propulsor requires the ability to predict the characteristics of both laminar and turbulent flows to a higher degree of accuracy. This report presents results of certain benchmark computations based on an upwind, high-resolution, finite-differencing Navier- Stokes solver. The purpose of the computations is to evaluate the ability, the accuracy and the performance of the solver in the simulation of detailed features of viscous ... |
|
| AGARD Fluid Dynamics Panel Meeting and Symposium on The Characterisation and Modification of Wakes from Lifting Vehicles in Fluids, Trondheim , Norway, 20-23 May 1996 |
MAY 96 |
|
| Authors:
W. J. McCroskey; ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRAN CE)
|
| The Fluid Dynamics Panel of AGARD arranged a Symposium on 'The Characterization and Modification of Wakes from Lifting Vehicles in Fluids,' on 20-23 May 1996 in Trondheim, Norway. The purpose of the Symposium was to review and discuss recent developments in wake research for aircraft and the implications for air traffic regulations, with a clear emphasis on the hazard of vortex encounters in civil aviation. Sessions were devoted specifically to ... |
|
| Analysis of Ship Deployed Line Array Dynamics |
MAR 96 |
55 pages |
| Authors:
David S. Hammond; NAVAL AIR WARFARE CENTER AIRCRAFT DIV WARMINSTER PA
|
| Airborne Rapidly Deployable Technology (ARDT) is being investigated by the US Navy. One of the areas crucial for the project's a success is an in- water deployment of an array. In a recent trial, instrumented arrays were deployed from a moving ship and allowed to descend to the bottom. The purpose of this trial was to demonstrate an ability to deploy a long array of sensors in this manner such ... |
|
| Vorticity Control for Efficient Propulsion |
FEB 96 |
|
| Authors:
Jamie M. Anderson; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| Vorticity control is a new paradigm in propulsion hydrodynamics. In this thesis, we study fish-like propulsion strategies as concepts in vorticity control. We investigated the flow around a swimming fish, the propulsive properties of a rigid oscillating foil and the interaction of an oscillating foil with upstream vorticity. Digital particle image velocimetry (DPIV) was used to make quantitative multipoint measurements of the unsteady flow fields. Fish are the prime example ... |
|
| Development of a Towed Underwater Launch Platform |
96 |
10 pages |
| Authors:
K. N. Parthasarathy; B. E. McGrath; D. A. Frostbutter; J. J. Wozniak; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| The concept of a new test facility to evaluate the underwater launch and flight performance of full-scale missiles and associated launcher systems is described. Results from preliminary studies on estimates of the platform dimensions hydrodynamic characteristics, and platform response to a missile launch impulse are included. The VSAERO panel method code was used to generate hydrodynamic force and moment coefficients for the condition of steady tow at 5 knots. These ... |
|
| Montgomery Point Lock and Dam Gate Study: Report 1. Hydraulic Forces and Characteristics Acting on Spillway Gates |
NOV 95 |
108 pages |
| Authors:
Bobby P. Fletcher; Luis A. DE Bejar; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS LAB
|
| Model tests of the navigation pass spillway proposed for the Montgomery Point Lock and Dam project were conducted with various anticipated pool and tailwater elevations and spillway gate positions to determine the hydraulic forces acting on the spillway gate, hydraulic characteristics of the spillway, stilling basin energy dissipation, and stability of riprap in the approach and exit channels from the spillway. The 1:15-scale section model simulated a 90-ft approach and ... |
|
Reports by Keyword(s)
HYDRODYNAMIC CHARACTERISTICS
