DOCSLIB.ORG

Micro Ocean Renewable Energy

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Micro Ocean Renewable Energy Micro Ocean Renewable Energy Harvesting ocean kinetic energy to power sonobuoys, navigational aids, weather buoys, emergency rescue devices, domain awareness sensors and fishery devices a Small Business Innovative Research proposal submitted to: The Naval Air Systems Command Acoustic Systems Division, Code 4.5.14 Naval Air Warfare Center Patuxent River, Maryland 20670 submitted by: Tocreo Mark Krawczewicz Eric Greene Labs Tocreo Labs Eric Greene Associates 410.562.9846 410.263.1348 e [email protected] [email protected] Tocreo Labs Eric Greene Associates, Inc. Table of Contents Background .....................................................................................................................................................2 Abstract ...........................................................................................................................................................2 Anticipated Benefits ........................................................................................................................................2 Keywords ........................................................................................................................................................2 Identification and Significance of the Problem or Opportunity.......................................................................3 Phase I Technical Objectives...........................................................................................................................5 Phase I Work Plan ...........................................................................................................................................5 Task 1. Determine Mechanical Wave Energy Extraction Potential.............................................................5 Task 2. Investigate Piezoelectric Energy Harvesting ..................................................................................7 Task 3. Investigate Rotary Magnetic Generator ..........................................................................................9 Task 4. Investigate Linear Magnetic Generators.......................................................................................10 Task 5. Design Power Storage Architecture..............................................................................................11 Task 6. Design Deployable Energy Harvesting Systems...........................................................................13 Phase I Option Work Plan .............................................................................................................................17 Related Work.................................................................................................................................................18 Relationship with Future Research or Research and Development...............................................................18 Key Personnel................................................................................................................................................22 Facilities/Equipment......................................................................................................................................24 References .....................................................................................................................................................25 Figures and Tables Figure 1. Sea State Wave Characteristics and Average Global Distribution..................................................3 Figure 2. Schematic Representation of Proposed Wave Energy Harvesting Systems to be Investigated.......4 Figure 3. Schematic of a Traveling Surface Wave .........................................................................................6 Figure 4. Constant-pressure Surface and Particle Orbits in a Trochoidal Wave ............................................6 Table 1. Estimated Compliance Cable Forces................................................................................................6 Figure 5. Maximum Available Kinetic Energy from Heaving Buoy as a Function of Wind Speed...............7 Figure 6. Piezo Stack Arrangement................................................................................................................8 Figure 7. Equivalent Electrical Model of the Piezo Power System................................................................8 Figure 8. Rotary Magnetic Generator Components........................................................................................9 Figure 9. Recoil Mechanism...........................................................................................................................9 Figure 10. Configuration of Gearing System for Rotary Magnetic Generator ...............................................9 Figure 11. Rotary Generator.........................................................................................................................10 Figure 12. Cross-Sectional View of a Linear Generator...............................................................................10 Figure 13. Floating Point Absorber with Submerged Damper Plate ............................................................10 Figure 14. Power Storage Architecture ........................................................................................................11 Figure 15. Infinite Power Solutions Micro-Energy Cell and Characteristics ...............................................12 Figure 16. Estimated Size of the Micro Energy Cell....................................................................................12 Figure 17. Estimated Size of Optional Primary Battery for Evaluation .......................................................13 Figure 18. Cross Sectional view of AN/SSQ-101 Showing Relative Volumes............................................14 Figure 19. MIT’s RoboTuna and Our Inspiration for A Wave Energy Extraction Fin.................................14 Figure 20. Tuna Fins for Ruggedized Laminated Piezo Energy Harvesting Concept ..................................15 Figure 21. Piezo Stack Deployment Sequence .............................................................................................15 Figure 22. Tuna Fins for Wave Linear Magnetic Generator Concept ..........................................................15 Figure 23. Proposed Tuna Fin Deployment Sequence .................................................................................16 Figure 24. Proposed Work Plan Schedule ....................................................................................................17 Figure 25. ~50um Thick Thin Film Printed Circuit Board Examples ..........................................................18 Figure 26. Direct Silver Printed Circuit Board.............................................................................................19 Figure 27. Line & Space Widths using Nano-Silver Traces and Conductive Silver Film on PET Cured from Nanoparticles Precursor.....................................................................................................19 Figure 28. AN/SSQ-101 Deployment Sequence ..........................................................................................21 Figure 29. Schematic of the U.S.Naval Academy’s 120-foot Wave Tank; Co-Investigator Mark Krawczewicz alongside the Tank; and Photos of the Tank’s Wave-making Mechanism ...........24 Ocean Energy Harvesting for Sonobuoys page 1 Using Kinetic Energy Devices Tocreo Labs Eric Greene Associates, Inc. Background The U.S. Navy spends over $100 million annually on sonobuoys to increase our undersea domain awareness. The AN/SSQ-101 Air Deployable Active Receiver is the most capable sonobuoy the Navy has ever deployed, yet it costs over $5k per unit and has a maximum operating life of only 8 hours. The Naval Air Systems Command (NAVAIR) has issued a Small Business Innovative Research (SBIR) solicitation for energy harvesting devices that could be fitted to the AN/SSQ-101. Mark Krawczewicz of Tocreo Labs and Eric Greene of Eric Greene Associates, Inc. have teamed to develop novel ocean kinetic energy harvesting techniques for sonobuoys and other floating electronic systems. Mr. Krawczewicz has over 25 of experience developing advanced electronic systems for the National Security Agency and private industry. Eric Greene Associates has conducted R & D for the U.S. Navy and commercial clients since 1988. We view this SBIR project as an opportunity to utilize a variety of emerging U.S. technologies to pioneer the field of Micro Ocean Renewable Energy. Abstract The AN/SSQ-101 Air Deployable Active Receiver (ADAR) sonobuoy has evolved as a vital Anti- Submarine Warfare (ASW) tool, with the ability to deploy a sophisticated hydrophone array from a single A-size canister. We are proposing the evaluation, modeling, simulation, and characterization of three kinetic energy harvesting technologies: 1. Piezo-Ceramic Device – utilizes a newly-developed ruggedized laminated piezo (RLP) device as the “micro-power” solution to convert relative wave motion to electrical energy. RLP is a mechanically simple design accommodated into a small volume. 2. Rotary Magnetic Generator – a traditional rotary geometry micro-generator with an innovative mechanism to continually spin the generator from the low frequency waves. 3. Linear Magnetic Generator – a novel magnet/coil device that can be deployed from the AN/SSQ-101. Anticipated Benefits There is significant opportunity to utilize emerging micro-energy
Load more

Recommended publications
  • Waves and Structures
    WAVES AND STRUCTURES By Dr M C Deo Professor of Civil Engineering Indian Institute of Technology Bombay Powai, Mumbai 400 076 Contact: [email protected]; (+91) 22 2572 2377 (Please refer as follows, if you use any part of this book: Deo M C (2013): Waves and Structures, http://www.civil.iitb.ac.in/~mcdeo/waves.html) (Suggestions to improve/modify contents are welcome) 1 Content Chapter 1: Introduction 4 Chapter 2: Wave Theories 18 Chapter 3: Random Waves 47 Chapter 4: Wave Propagation 80 Chapter 5: Numerical Modeling of Waves 110 Chapter 6: Design Water Depth 115 Chapter 7: Wave Forces on Shore-Based Structures 132 Chapter 8: Wave Force On Small Diameter Members 150 Chapter 9: Maximum Wave Force on the Entire Structure 173 Chapter 10: Wave Forces on Large Diameter Members 187 Chapter 11: Spectral and Statistical Analysis of Wave Forces 209 Chapter 12: Wave Run Up 221 Chapter 13: Pipeline Hydrodynamics 234 Chapter 14: Statics of Floating Bodies 241 Chapter 15: Vibrations 268 Chapter 16: Motions of Freely Floating Bodies 283 Chapter 17: Motion Response of Compliant Structures 315 2 Notations 338 References 342 3 CHAPTER 1 INTRODUCTION 1.1 Introduction The knowledge of magnitude and behavior of ocean waves at site is an essential prerequisite for almost all activities in the ocean including planning, design, construction and operation related to harbor, coastal and structures. The waves of major concern to a harbor engineer are generated by the action of wind. The wind creates a disturbance in the sea which is restored to its calm equilibrium position by the action of gravity and hence resulting waves are called wind generated gravity waves.
    [Show full text]
  • Arxiv:1903.11909V1 [Physics.Flu-Dyn] 28 Mar 2019
    Exact solution for progressive gravity waves on the surface of a deep fluid Nail S. Ussembayev∗ Computer, Electrical, and Mathematical Sciences and Engineering Divison King Abdullah University of Science and Technology, Thuwal 23955-6900, KSA Gerstner or trochoidal wave is the only known exact solution of the Euler equations for periodic surface gravity waves on deep water. In this Letter we utilize Zakharov’s variational formulation of weakly nonlinear surface waves and, without truncating the Hamiltonian in its slope expansion, derive the equations of motion for unidirectional gravity waves propagating in a two-dimensional flow. We obtain an exact solution of the evolution equations in terms of the Lambert W -function. The associated flow field is irrotational. The maximum wave height occurs for a wave steepness of 0.2034 which compares to 0.3183 for the trochoidal wave and 0.1412 for the Stokes wave. Like in the case of Gerstner’s solution, the limiting wave of a new type has a cusp of zero angle at its crest. Background.—The water waves problem even in the tial evaluated on the free surface. The expansion coef- completely idealized setting of a perfect fluid is notori- ficients simplify remarkably for two-dimensional waves ously difficult from a mathematical point of view. This propagating in the same direction and the infinite series is one of the reasons we have very few explicit solutions can be summed in a closed form if the wave steepness to the fully nonlinear free-surface hydrodynamics equa- is small. From the stationary periodic solution of the tions despite extensive research over hundreds of years.
    [Show full text]
  • Realistic Simulation of Ocean Surface Using Wave Spectra Jocelyn Fréchot
    Realistic simulation of ocean surface using wave spectra Jocelyn Fréchot To cite this version: Jocelyn Fréchot. Realistic simulation of ocean surface using wave spectra. Proceedings of the First International Conference on Computer Graphics Theory and Applications (GRAPP 2006), 2006, Por- tugal. pp.76–83. hal-00307938 HAL Id: hal-00307938 https://hal.archives-ouvertes.fr/hal-00307938 Submitted on 29 Jul 2008 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. REALISTIC SIMULATION OF OCEAN SURFACE USING WAVE SPECTRA Jocelyn Frechot´ LaBRI - Laboratoire bordelais de recherche en informatique Domaine universitaire, 351 cours de la Liber´ ation, 33405 Talence CEDEX, France [email protected] Keywords: Natural phenomena, realistic ocean waves, procedural animation, parametric energy spectra Abstract: We present a method to simulate ocean surfaces away from the coast, with correct statistical wave height and direction distributions. By using classical oceanographic parametric wave spectra, our results fit real world measurements, without depending on them. Since wave spectra are independent of the ocean model, Gerstner parametric equations and Fourier transform method can be used with them. Moreover, since they are simple to use and need very few parameters, they allow easy production of ocean surface animations usable in movies and games.
    [Show full text]
  • Guide Wave Analysis and Forecasting
    WORLD METEOROLOGICAL ORGANIZATION GUIDE TO WAVE ANALYSIS AND FORECASTING 1998 (second edition) WMO-No. 702 WORLD METEOROLOGICAL ORGANIZATION GUIDE TO WAVE ANALYSIS AND FORECASTING 1998 (second edition) WMO-No. 702 Secretariat of the World Meteorological Organization – Geneva – Switzerland 1998 © 1998, World Meteorological Organization ISBN 92-63-12702-6 NOTE The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the World Meteorological Organization concerning the legal status of any country, territory, city or area, or of its authorities or concerning the delimitation of its fontiers or boundaries. CONTENTS Page FOREWORD . V ACKNOWLEDGEMENTS . VI INTRODUCTION . VII Chapter 1 – AN INTRODUCTION TO OCEAN WAVES 1.1 Introduction . 1 1.2 The simple linear wave . 1 1.3 Wave fields on the ocean . 6 Chapter 2 – OCEAN SURFACE WINDS 2.1 Introduction . 15 2.2 Sources of marine data . 16 2.3 Large-scale meteorological factors affecting ocean surface winds . 21 2.4 A marine boundary-layer parameterization . 27 2.5 Statistical methods . 32 Chapter 3 – WAVE GENERATION AND DECAY 3.1 Introduction . 35 3.2 Wind-wave growth . 35 3.3 Wave propagation . .36 3.4 Dissipation . 39 3.5 Non-linear interactions . .40 3.6 General notes on application . 41 Chapter 4 – WAVE FORECASTING BY MANUAL METHODS 4.1 Introduction . 43 4.2 Some empirical working procedures . 45 4.3 Computation of wind waves . 45 4.4 Computation of swell . 47 4.5 Manual computation of shallow-water effects . 52 Chapter 5 – INTRODUCTION TO NUMERICAL WAVE MODELLING 5.1 Introduction .
    [Show full text]
  • Downloaded 09/27/21 10:05 AM UTC 166 JOURNAL of PHYSICAL OCEANOGRAPHY VOLUME 43
    JANUARY 2013 C O N S T A N T I N 165 Some Three-Dimensional Nonlinear Equatorial Flows ADRIAN CONSTANTIN* King’s College London, London, United Kingdom (Manuscript received 28 March 2012, in final form 11 October 2012) ABSTRACT This study presents some explicit exact solutions for nonlinear geophysical ocean waves in the b-plane approximation near the equator. The solutions are provided in Lagrangian coordinates by describing the path of each particle. The unidirectional equatorially trapped waves are symmetric about the equator and prop- agate eastward above the thermocline and beneath the near-surface layer to which wind effects are confined. At each latitude the flow pattern represents a traveling wave. 1. Introduction The aim of the present paper is to provide an explicit nonlinear solution for geophysical waves propagating The complex dynamics of flows in the Pacific Ocean eastward in the layer above the thermocline and beneath near the equator presents certain specific features. The the near-surface layer in which wind effects are notice- equatorial region is characterized by a thin, permanent, able. The solution is presented in Lagrangian coordinates shallow layer of warm (and less dense) water overlying by describing the circular path of each particle. Within a deeper layer of cold water. The two layers are separated a narrow equatorial band the flow pattern describes an byasharpthermocline and a plausible assumption is that equatorially trapped wave that is symmetric about the there is no motion in the deep layer—see, for example, equator: at each fixed latitude we have a traveling wave Fedorov and Brown (2009).
    [Show full text]
  • Arxiv:1907.10998V2
    Parametric solutions of the generalized short pulse equations Yoshimasa Matsunoa Division of Applied Mathematical Science, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Yamaguchi 755-8611, Japan Abstract We consider three novel PDEs associated with the integrable generalizations of the short pulse equation classified recently by Hone et al (2018 Lett. Math. Phys. 108 927-947). In particular, we obtain a variety of exact solutions by means of a direct method analogous to that used for solving the short pulse equation. The main results reported here are the parametric representations of the multisoliton solutions. These solutions include cusp solitons, unbounded solutions with finite slope and breathers. In addition, the cusped periodic wave solutions are constructed from the cusp solitons by means of a simple procedure. As for non-periodic solutions, smooth breather solutions are of particular interest from the perspective of applications to real physical phenomena. The cycloid reduced from the periodic traveling wave with cusps is also worth remarking in connection with Gerstner’s trochoidal solution in deep gravity waves. A number of works are left for future study, some of which will be addressed in concluding remarks. arXiv:1907.10998v2 [nlin.SI] 17 Mar 2020 aE-mail address: [email protected] 1 1. Introduction The short pulse (SP) equation is a completely integrable partial differential equation (PDE) in the sence that it admits a Lax pair and an infinite number of conservation laws [1]. It can be written in an appropriate dimensionless form as 1 u = u + (u3) , (1.1) xt 6 xx where u = u(x, t) represents a scalar function of x and t, and subscripts x and t appended to u denote partial differentiations.
    [Show full text]
  • Ssc-475 Guidelines for Evaluation of Marine Finite
    NTIS #PB2019-###### SSC-475 GUIDELINES FOR EVALUATION OF MARINE FINITE ELEMENT ANALYSES Editors: Dr. E.D. Wang, Mr. J.S. Bone, Dr. M. Ma, and Mr. A. Dinovitzer This document has been approved for public release and sale; its distribution is unlimited. SHIP STRUCTURE COMMITTEE 2019 SHIP STRUCTURE COMMITTEE RDML Richard Timme RADM Lorin Selby U. S. Coast Guard Assistant Commandant Chief Engineer and Deputy Commander for Prevention Policy (CG-5P) For Naval Systems Engineering (SEA05) Co-Chair, Ship Structure Committee Co-Chair, Ship Structure Committee Mr. Jeffrey Lantz Mr. Derek Novak Director, Commercial Regulations and Standards (CG-5PS) Senior Vice President, Engineering & Technology U.S. Coast Guard American Bureau of Shipping Mr. H. Paul Cojeen Dr. John MacKay Society of Naval Architects and Marine Engineers Head, Warship Performance, DGSTCO Defence Research & Development Canada - Atlantic Mr. Kevin Kohlmann Mr. Luc Tremblay Director, Office of Safety Executive Director, Domestic Vessel Regulatory Oversight Maritime Administration and Boating Safety, Transport Canada Mr. Albert Curry Mr. Eric Duncan Deputy Assistant Commandant for Engineering and Group Director, Ship Integrity and Performance Engineering Logistics (CG-4D) (SEA 05P) U.S. Coast Guard Naval Sea Systems Command Mr. Neil Lichtenstein Dr. Thomas Fu Deputy Director N7x, Engineering Directorate Director, Ship Systems and Engineering Research Division Military Sealift Command Office of Naval Research SHIP STRUCTURE SUB-COMMITTEE UNITED STATES COAST GUARD (CVE) AMERICAN BUREAU OF SHIPPING CAPT Robert Compher Mr. Daniel LaMere Mr. Jaideep Sirkar Ms. Christina Wang Mr. Charles Rawson SOCIETY OF NAVAL ARCHITECTS AND MARINE DEFENCE RESEARCH & DEVELOPMENT CANADA ENGINEERS ATLANTIC Mr. Frederick Ashcroft Dr. Malcolm Smith Dr.
    [Show full text]
  • Dispersion Kernels for Water Wave Simulation
    Dispersion Kernels for Water Wave Simulation Jose´ A. Canabal1 David Miraut1 Nils Thuerey2 Theodore Kim3;4 Javier Portilla5 Miguel A. Otaduy1 1URJC Madrid 2Technical University of Munich 3Pixar Animation Studios 4Universiy of California, Santa Barbara 5Instituto de Optica, CSIC Figure 1: Rain on the pond. Our wave simulation method captures the gravity waves present in the wakes produced by the paper birds, as well as the capillary waves produced by rain drops, all with correct scale-dependent velocities. The waves reflect on all the objects in the scene, both static and dynamic. The domain is 4 meters wide, and is simulated on a 1024 × 1024 grid, at just 1:6 sec. per frame. Abstract thesizing height field waves with correct dispersion [Tessendorf 2004b]. However, handling obstacle boundaries in the frequency We propose a method to simulate the rich, scale-dependent dynam- domain is computationally expensive, and quickly renders any ap- ics of water waves. Our method preserves the dispersion proper- proach in this direction impractical. Thus, users have to resort to lo- ties of real waves, yet it supports interactions with obstacles and is calized three-dimensional simulations [Nielsen and Bridson 2011], computationally efficient. Fundamentally, it computes wave accel- precomputations [Jeschke and Wojtan 2015], or height field ap- erations by way of applying a dispersion kernel as a spatially variant proaches with spatial filtering techniques [Kass and Miller 1990; filter, which we are able to compute efficiently using two core tech- Tessendorf 2008]. While the latter methods are typically fast, they nical contributions. First, we design novel, accurate, and compact only roughly approximate or even neglect dispersion effects.
    [Show full text]
  • The Effect of Foreshore Slope on Breakwater Stability Henk Jan Verhagen1
    The effect of foreshore slope on breakwater stability Henk Jan Verhagen1 The problem history In case of coasts with steep foreshores coastal structures suffer more from damage than normally could be expected from given boundary conditions at deep water. For that reason in many guidelines it is recommended to apply a heavier class of rock in those cases; manufacturers of single layer units (like Accropode, Core-loc or Xbloc) recommend a lower Kd value in case of a steep foreshore. Unfortunately until recently there was no insight in the physical processes leading to this extra load. In the stability formula of VAN DER MEER [1988] shallow water and steep foreshores are not considered. The original formula (for plunging conditions) of Van der Meer reads: 1 5 H − ⎛⎞S s = cPξ 0.5 0.18 (1) ∆ plunging ⎜⎟ Dn50 ⎝⎠N The coefficient cplunging has a value of 5.0 A first step into a more systematic analysis of problem of shallow water and steep foreshores has been the systematic research on the interaction between waves and structures in case of shallow foreshores by VAN GENT ET AL.[2003]. The main result of this research was that the load on the structure can better described by a shallow water spectrum at the toe of the structure. And because the longer periods are more relevant than the shorter periods, more weight should be given to the low frequency part of the spectrum. This can be done by using in stability formula as parameter for the wave energy not the Tp or Tm0, but the Tm-1,0.
    [Show full text]
  • The Absence of Stokes Drift in Waves
    The Absence of Stokes Drift in Waves Clifford Chafin Department of Physics, North Carolina State University, Raleigh, NC 27695 ∗ June 21, 2021 Abstract Stokes drift has been as central to the history of wave theory as it has been distressingly ab- sent from experiment. Neither wave tanks nor experiments in open bodies detect this without nearly canceling \eulerian flows." Acoustic waves have an analogous problem that is particu- larly problematic in the vorticity production at the edges of beams. Here we demonstrate that the explanation for this arises from subtle end-of-packet and wavetrain gradient effects such as microbreaking events and wave-flow decomposition subtleties required to conserve mass and momentum and avoid fictitious external forces. These losses occur at both ends of packets and can produce a significant nonviscous energy loss for translating and spreading surface wave packets and wavetrains. In contrast, monochromatic sound wave packets will be shown to asymmetrically distort to conserve momentum. This provides an interesting analogy to how such internal forces arise for gradients of electromagnetic wavetrains in media. Such examples show that the interactions of waves in media are so system dependent as to be completely nonuniversal. These give further examples of how boundary effects must be carefully consid- ered for conservation laws especially when harmonic functions are involved. The induced flows in establishing surface waves are shown to be time changing and dependent on wave history and suggest that some classical work based on mass flux and wave interactions may need to be reconsidered. 1 Introduction The theory of waves in media has been an important spawning and testing ground for many of the topics of modern mathematical physics.
    [Show full text]
  • Wind Wave - Wikipedia 1 of 16
    Wind wave - Wikipedia 1 of 16 Wind wave In fluid dynamics, wind waves, or wind-generated waves, are water surface waves that occur on the free surface of bodies of water. They result from the wind blowing over an area of fluid surface. Waves in the oceans can travel thousands of miles before reaching land. Wind waves on Earth range in size from small ripples, to waves over 100 ft (30 m) high.[1] When directly generated and affected by local waters, a Large wave wind wave system is called a wind sea. After the wind ceases to blow, wind waves are called swells. More generally, a swell consists of wind-generated waves that are not significantly affected by the local wind at that time. They have been generated elsewhere or some time ago.[2] Wind waves in the ocean are called ocean surface waves. Wind waves have a certain amount of randomness: Video of large waves from Hurricane Marie along the coast of Newport subsequent waves differ in height, duration, and shape Beach, California with limited predictability. They can be described as a stochastic process, in combination with the physics governing their generation, growth, propagation, and decay—as well as governing the interdependence between flow quantities such as: the water surface movements, flow velocities and water pressure. The key statistics of wind waves (both seas and swells) in evolving sea states can be predicted with wind wave models. Although waves are usually considered in the water seas Ocean waves of Earth, the hydrocarbon seas of Titan may also have wind-driven waves.[3] Contents Formation Types https://en.wikipedia.org/wiki/Wind_wave Wind wave - Wikipedia 2 of 16 Spectrum Shoaling and refraction Breaking Physics of waves Models Seismic signals See also References Scientific Other External links Formation The great majority of large breakers seen at a beach result from distant winds.
    [Show full text]
  • Merchant Ships
    WAKEOF MERCHANT SHIPS B Y SVEND AAGE HARVALD THE DANISH TECHNICALPRESS COPENHAGEN 1950 ..'M . I / ;4 i) .; ,# 3.. - ' f- f .- t ':. -- . , f ç.. - t : . '.- ,.. Denne afhand].ing er s.f Daninarks tekniske Hjsko1e antaget tu Í'orsvar for den tekniske doktorgrad. Danmarks tekniske Højs1o1e,.23. juni1950. Anker Engelund. Rektor. PREFACE. It is the hope.of the author that this treatise will be a help and guidance to the designer in the shipyard as well as. tothe scientist working in the laboratory. The dissertation princlpally.dea].s with.the problems connected with wake, seen partly from a practical, partly from a theoretical point Of view; but further It, considers questions closely connected tò wake. Thus amongst others the problem of thrust deduction has been taken.up fora. brief discussion, The principal part of the, work connected with this treatise has been carried out at the shipbuilding depart- ment at the DANMARXSTEKNIS HØJSKOLE, Køberthavn.The. leader of this department ProfessorC.. PROHASKA, D.Sc., has during the progress-of the work given the author a great deal ol' sùpport and assistance. Some of the work had.to be done abroad, partly in Sweden and partly in Holland. In Sweden the author hada whole series of experiments performed and in Holland stati- stical material was collected. For five nontha the author was temporarily employed as half-day assistant at the STATENS SKEPPSP,ROVNI.NGSANSTALT, Gtoborg, under Professor. H.F.NORDSTROM, D.So,superinten- dent. During this same period the HUGOHAMMRS FOND FR IN- TERNATIONELL FORSKNING INOM SJFARTENsupplied the funds enabling the carrying out, of model experiments.
    [Show full text]