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Energy cascades in the upper ocean

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Chinese Journal of Oceanology and Limnology 2006年第3期24卷 225-235页

作者： Ray Q.Lin Scott Chubb Hydromechanics Directorate David Taylor Research Center carderock division West Bethesda MD 20817-5700 USA Remote Sensing Division Naval Research Laboratory Washington DC 20375-5351 USA

Wave-wave interactions cause energy cascades. These are the most important processes in the upper ocean because they govern wave-growth and dissipation. Through indirect cascades, wave en- ergy is transferred from higher frequencies to lower frequencies, leading to wave growth. In direct cas- cades, energy is transferred from lower frequencies to the higher frequencies, which causes waves to break, and dissipation of wave energy. However, the evolution and origin of energy cascade processes are still not fully understood. In particular, for example, results from a recent theory (Kalmykov, 1998) sug- gest that the class I wave-wave interactions (defined by situations involving 4-, 6-, 8-, etc, even numbers of resonantly interacting waves) cause indirect cascades, and Class II wave-wave interactions (involving, 5-, 7-, 9-, etc, .., odd numbers of waves) cause direct cascades. In contrast to this theory, our model results indicate the 4-wave interactions can cause significant transfer of wave energy through both direct and in- direct cascades. In most situations, 4-wave interactions provide the major source of energy transfer for both direct cascades and indirect cascades, except when the wave steepness is larger than 0.28. Our model results agree well with wave measurements, obtained using field buoy data (for example, Lin and Lin, 2002). In particular, in these observations, asymmetrical wave-wave interactions were studied. They found that direct and indirect cascades both are mainly due to the 4-wave interactions when wave steep- ness is less than 0.3.

关键词：非线性动力海洋气候能量层叠波浪

Peridynamic Solutions for Timoshenko Beams

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Engineering（科研） 2014年第6期6卷 304-317页

作者： E. Thomas Moyer Michael J. Miraglia Naval Surface Warfare Center/carderock division W. Bethesda USA

Peridynamics is a recently developed formulation for continuum mechanics which describes material deformation using a nonlocal approach. Unlike Classical Continuum Mechanics (CCM) where the conservation equations are cast into partial differential equations, Peridynamics describes the deformation in terms of integro-differential equations. Additionally, peridynamics permits a natural length scale that is absent in CCM. This facilitates the modeling of complex material behavior and fracture which is not dependent on the numerical discretization length scale. In this paper, we develop a Peridynamic formulation for a Timoshenko beam. Full details and numerical examples are presented for both bending and axial behavior. While the development in this paper is limited to elastic, infinitesimal deformations, the approach can be extended to finite inelastic deformations.

关键词： Peridynamics Timoshenko Beam Beam Bending Dynamic Deformation

Nonlinear wave-wave interactions and wedge waves

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Chinese Journal of Oceanology and Limnology 2005年第2期23卷 129-143页

作者： Ray Q.Lin Will Perrie Hydromechanic Directorate David Taylor Model Basin Carderock Division 9500 MacArthur Boulevard West Bethesda MD 20817-5700 USAOcean Sciences Division Maritimes Region Fisheries and Oceans Canada Bedford Institute of Oceanography Dartmouth Nova Scotia Canada B2Y 4A2

A tetrad mechanism for exciting long waves, for example edge waves, is described based on nonlinear resonant wave-wave interactions. In this mechanism, resonant interactions pass energy to an edge wave, from the three participating gravity waves. The estimated action flux into the edge wave can be orders of magni- tude greater than the transfer fluxes derived from other competing mechanisms, such as triad interactions. More- over, the numerical results show that the actual transfer rates into the edge wave from the three participating gravity waves are two- to three- orders of magnitude greater than bottom friction.

关键词：非线性波-波作用四次-三元组引力波边缘波平行作用振动振幅

RADIATED NOISE MEASUREMENTS FOR A NATIONAL OCEANOGRAPHIC ATMOSPHERIC ADMINISTRATION （NOAA） FISHERIES SURVEY VESSEL

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RADIATED NOISE MEASUREMENTS FOR A NATIONAL OCEANOGRAPHIC ATM...

Acoustic Supercoupling in a Zero-Compressibility Waveguide

The Second International Symposium on Advanced Technology of Vibration and Sound

作者： Kevin F.O’Neill Michael P.Schilt Naval Surface Warfare Center carderock division West Bethesda ONR

＜正＞This report contains the results of the December 2004 measurement of acoustic underwater radiated noise of the R/V OSCAR DYSON （R 224）.One-third octave band source levels are provided at a variety of ship speeds along with frequencies,levels,and sources of significant tones detected.The final radiated noise results are compared to and below the ICES specification.

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Research 2019年第1期2019卷 1086-1095页

作者： H.Esfahlani M.S.Byrne M.McDermott A.Alù Photonics Initiative Advanced Science Research CenterCity University of New YorkNew York CityNY 10031USA Department of Electrical and Computer Engineering Te University of Texas at AustinAustinTX 78712USA Electrical Engineering Institute Ecole Polytechnique Fed´erale de Lausanne(EPFL)CH-1015 LausanneSwitzerland Naval Surface Warfare Center carderock division West BethesdaMD 20817USA Physics Program Graduate CenterCity University of New YorkNew York CityNY 10026USA Department of Electrical Engineering City College of New YorkNew York CityNY 10031USA

Funneling acoustic waves through largely mismatched channels is of fundamental importance to tailor and transmit sound for a variety of applications.In electromagnetics,zero-permittivity metamaterials have been used to enhance the coupling of energy in and out of ultranarrow channels,based on a phenomenon known as supercoupling.Tese metamaterial channels can support total transmission and complete phase uniformity,independent of the channel length,despite being geometrically mismatched with their input and output ports.In the feld of acoustics,this phenomenon is challenging to achieve,since it requires zero-density metamaterials,typically realized with waveguides periodically loaded with membranes or resonators.Compared to electromagnetics,the additional challenge is due to the fact that conventional acoustic waveguides do not support a cut-of for the dominant mode of propagation,and therefore zero-index can be achieved only based on a collective resonance of the loading elements.Here we propose and experimentally realize acoustic supercoupling in a dual regime,using a compressibility-nearzero acoustic channel.Rather than engineering the channel with subwavelength inclusions,we operate at the cut-of of a higherorder acoustic mode,demonstrating the realization and efcient excitation of a zero-compressibility waveguide with efective sof boundaries.We experimentally verify strong transmission through a largely mismatched channel and uniform phase distribution,independent of the channel length.Our results open interesting pathways towards the realization of extreme acoustic parameters and their implementation in relevant applications,such as ultrasound imaging,acoustic transduction and sensing,nondestructive evaluation,and sound communications.

关键词： waveguide coupling realization

Technology Integration On Cargo Handling Systems

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Technology Integration On Cargo Handling Systems

作者： Mark DiTroia Daniel Feeney Suzanne Kralle Naval Surface Warfare Center Carderock DivisionShip SystemsEngineering Station(Code 9732)Philadelphia.PAUSA

Naval cargo handling systems have traditionally been designed as two independent systems:the hardware itself and theinformation systems that control operation.This lack of integration often posed difficulties.The operator might not discover that alimit switch needed repair until performing the tedious process of routine maintenance,or when the system failed to operate and anextensive troubleshooting procedure followed.With today’s technology,however,that has all changed.Smart switches and sensors.automated maintenance devices,and programmable logic controllers are integrated via networks such as DeviceNet and Ethernet toform the new generation of cargo handling systems.These systems not only reduce workload and manning through more powerfultroubleshooting tools and semi-automation,but they also decrease system downtime and maintenance costs by being able to identifymaintenance concerns before they cause a failure.Exploration of the integrated networks installed on vertical package conveyors aspart of the Smart Carrier Program will illustrate how new technology and integrated networks are currently being applied to Navalcargo handling systems and how they might be used to further reduce shipboard workload,manning,and maintenance costs in theyears to come.

关键词： integrated networks cargo handling systems programmable logic controller

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传统立体印刷材料系统的开发工艺

中国印刷与包装研究 2010年第2期2卷 71-72页

作者： Ben R. Utela Duane Storti Rhonda L.Anderson Mark Ganter 曹华(编译) Department of Mechanical Bioengineering University of Washington Department of Mechanical Engineering University of Washington U.S. Navy--Naval Surface Warfare Center Panama City Division (NSWC-PCD) 不详

如果缺少对立体印刷(3DP)技术的研究经验将难以开发一种新型的应用于此领域的材料系统,因为立体印刷的灵活性要求其具有大量材料参数和工艺参数。本文详细介绍了开发立体印刷工艺的各个实施步骤,以及各个步骤中使用到的工具和注意事项... 详细信息

如果缺少对立体印刷(3DP)技术的研究经验将难以开发一种新型的应用于此领域的材料系统,因为立体印刷的灵活性要求其具有大量材料参数和工艺参数。本文详细介绍了开发立体印刷工艺的各个实施步骤,以及各个步骤中使用到的工具和注意事项。该材料系统的开发流程可以加深对立体印刷工艺的理解,帮助用户充分利用立体印刷的相对灵活性,加速新材料系统的发展。同时,本文以应用立体印刷材料系统开发高致密陶瓷牙制品为例,介绍立体印刷的灵活性。

关键词：立体印刷快速成型技术实体自由形状制造材料发展黏结料开发