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基于势流理论和OpenFOAM的耦合模型对多向不规则波浪的模拟

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水科学进展 2016年第1期27卷 88-99页

作者：季新然柳淑学 bo T.PAULSEN harry b.bingham 大连理工大学海岸和近海工程国家重点实验室辽宁大连116024 丹麦技术大学机械学院代尔夫特三角洲研究中心

基于势流理论的数值水池可以快速计算波浪的传播及其对建筑物的作用,但是势流理论是基于波浪的无黏性假设的,而在工程中,通常需要在固体边界及波浪破碎的区域考虑黏性效应。针对基于求解Navier-Stokes方程的黏性水池计算量较大、速度较... 详细信息

基于势流理论的数值水池可以快速计算波浪的传播及其对建筑物的作用,但是势流理论是基于波浪的无黏性假设的,而在工程中,通常需要在固体边界及波浪破碎的区域考虑黏性效应。针对基于求解Navier-Stokes方程的黏性水池计算量较大、速度较慢的缺点,采用耦合的方法模拟多向不规则波浪的传播,即在外域通过基于势流理论的数值水池产生多向不规则波浪,内域采用求解Navier-Stokes方程和流体体积法(VOF方法)对自由表面进行追踪,通过外域所提供的边界波浪,内域计算可以在较小区域进行计算,从而达到减少计算量、提高计算效率的目的。

关键词：势流理论 OpenFOAM 耦合多向不规则波浪

A Numerical Investigation of Gap and Shape Effects on a 2D Plunger-Type Wave Maker

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Journal of Marine Science and Application 2020年第1期19卷 101-115页

作者： Amir H.Nikseresht harry b.bingham Department of Mechanical Engineering Technical University of DenmarkDK-2800 Kgs LyngbyDenmark Department of Mechanical Engineering Shiraz University of TechnologyShiraz 71555-13876Iran

The installation of plunger-type wave makers in experimental tanks will generally include a gap between the back of the wedge and the wall of the *** this study,we analyze the influence of this gap on the wave making performance of the plunger using two-dimensional(2 D)CFD calculations for a range of nearly linear wave conditions and compare the results with both experimental measurements and linear potential flow *** wedge-shaped profiles,all with the same submerged volume,are ***,the generated waves are compared with the predictions of linear potential flow *** calculations are made using the commercial ANSYS FLUENT finite-volume code with dynamic meshes to solve the Navier-Stokes equations and the volume of fluid scheme to capture the air-water ***,the linear potential flow solution of Wu(J Hydraul Res 26:481-493,1988)is extended to consider an arbitrary profile and serve as a reference *** amplitude ratios of the generated waves predicted by the CFD calculations compare well with the predictions of linear potential flow theory for a simple wedge,indicating that viscous effects do not influence this ratio for small-amplitude motions in 2 *** contrast,significant higher harmonic components are produced by larger amplitude ***,the simple wedge is found to produce the smallest spurious higher harmonic content in the far-field wave.

关键词： Wave maker Plunger-type berkeley wedge Hyperbolic sine profile Gap Dynamic mesh Volume of fluid

Design and guidance of a multi-active debris removal mission

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Astrodynamics 2023年第4期7卷 383-399页

作者： Minduli C.Wijayatunga(b) Roberto Armellin harry Holt Laura Pirovano Aleksander A.Lidtke Te Pūnaha Atea–Space Institute The University of AucklandAuckland 1010New Zealand Astroscale Japan Inc. 1-16-4-16 KinshiSumida-kuTokyoJapan

Space debris have become exceedingly dangerous over the years as the number of objects in orbit continues to *** debris removal(ADR)missions have gained significant interest as effective means of mitigating the risk of collision between objects in *** study focuses on developing a multi-ADR mission that utilizes controlled reentry and *** mission comprises two spacecraft:a Servicer that brings debris to a low altitude and a Shepherd that rendezvous with the debris to later perform a controlled reentry.A preliminary mission design tool(PMDT)was developed to obtain time and fuel optimal trajectories for the proposed mission while considering the effect of J2,drag,eclipses,and duty *** PMDT can perform such trajectory optimizations for multi-debris missions with computational time under a *** guidance schemes are also studied,taking the PMDT solution as a reference to validate the design methodology and provide guidance solutions to this complex mission profile.

关键词： active debris removal(ADR) trajectory design optimization autonomous guidance low-thrust electric propulsion △u-law guidance Q-law guidance

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机遇,你抓对了么

董事会 2014年第12期 92-94页

作者： Christopher b.bingham Nathan R.Furr Kathleen M.Eisenhardt

一旦他们看准并研究透彻了特定市场上的机遇,就会制定一套聚焦战略,将注意力牢牢锚定他们认为最佳的机会,这会让战略家们一次性收获一个领域的多个机遇。

关键词：营销创意聚焦战略特定市场锚定执行阶段时间精力销售能力选择方式提供商成功概率

Propulsive matrix of a helical flagellum

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Chinese Physics b 2014年第11期23卷 51-56页

作者：张何朋刘斌 bruce Rodenborn harry L.Swinney Department of Physics and Astronomy and Institute of Natural Sciences School of Natural Sciences University of California Department of Physics and Center for Nonlinear Dynamics University of Texas at Austin

We study the propulsion matrix of bacterial flagella numerically using slender body theory and the regularized Stokeslet method in a biologically relevant parameter regime. All three independent elements of the matrix are measured by computing propulsive force and torque generated by a rotating flagellum, and the drag force on a translating flagellum. Nu- merical results are compared with the predictions of resistive force theory, which is often used to interpret micro-organism propulsion. Neglecting hydrodynamic interactions between different parts of a flagellum in resistive force theory leads to both qualitative and quantitative discrepancies between the theoretical prediction of resistive force theory and the numerical results. We improve the original theory by empirically incorporating the effects of hydrodynamic interactions and propose new expressions for propulsive matrix elements that are accurate over the parameter regime explored.

关键词： low-Reynolds-number flows micro-organism dynamics bacterial swimming

NEW METHOD FOR IMPROVED CALCULATIONS OF UNSTEADY COMPLEX FLOWS IN LARGE ARTERIES

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Acta Mathematica Scientia 2011年第6期31卷 2247-2264页

作者： A. Cheer harry A. Dwyer T. Kim Department of Mathematics One Shields AvenueUniversity of California Department of Mechanical and Aeronautical Engeering University of California

Using an improved computational fluid dynamics （CFD） method developed for highly unsteady three-dimensional flows, numerical simulations for oscillating flow cycles and detailed unsteady simulations of the flow and forces on the aortic vessels at the iliac bifurcation, for both healthy and diseased patients, are analyzed. Improvements in computational efficiency and acceleration in convergence are achieved by calculating both an unsteady pressure gradient which is due to fluid acceleration and a good global pressure field correction based on mass flow for the pressure Poisson equation. Applications of the enhanced method to oscillatory flow in curved pipes yield an order of magnitude increase in speed and efficiency, thus allowing the study of more complex flow problems such as flow through the mammalian abdominal aorta at the iliac arteries bifurcation. To analyze the large forces which can exist on stent graft of patients with abdominal aor- tic aneurysm （AAA） disease, a complete derivation of the force equations is presented. The accelerated numerical algorithm and the force equations derived are used to calculate flow and forces for two individuals whose geometry is obtained from CT data and whose respective blood pressure measurements are obtained experimentally. Although the use of endovascular stent grafts in diseased patients can alter vessel geometries, the physical characteristics of stents are still very different when compared to native blood vessels of healthy subjects. The geometry for the AAA stent graph patient studied in this investigation induced flows that resulted in large forces that are primarily caused by the blood pressure. These forces are also directly related to the flow cross-sectional area and the angle of the iliac arteries relative to the main descending aorta. Furthermore, the fluid flow is significantly disturbed in the diseased patient with large flow recirculation and stagnant regions which are not present for healthy subjects.

关键词： numerical computations fluid dynamics stent graphs blood pressure flow pressure

The Local Asymptotic behavior of Solutions of Second Order Linear Differential Equations in a Nutshell

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Journal of Mathematical Research with Applications 1993年第3期 337-350页

作者： harry Gingold Dept.of Math College of Arts and Sciences Morgantown:WV26505 U.S.A.

*** a second order linear differential equation with meromorphic coefficienta（x）y”+b（x）y’+c（x）y=0 （1.1）in,a domain D the local analytic theory for such equations is well developed,see e.g.[8].If xis a regular point for（1.1）then the theory advocates to utilize Taylor seriesexpansions of two linearly indepentdent solutions of（1.1）.If xis a regular singular pointfor（1.1）,Frobenius’method tells us to follow sometimes a laborious procedure which

关键词： exp The Local Asymptotic behavior of Solutions of Second Order Linear Differential Equations in a Nutshell

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非线性不规则波二阶分离模型

大连理工大学学报 2013年第6期53卷 871-878页

作者：阳志文柳淑学李金宣哈里 b.宾汉姆大连理工大学海岸和近海工程国家重点实验室辽宁大连116024 丹麦技术大学机械工程系

基于二阶波势流理论,建立了一个非线性不规则波浪二阶分离模型.通过求解频域内一、二阶成分之间的传递函数,建立起二阶项求解关系式,将二阶项变换到与一阶项同一个傅里叶频域空间,采用Newton-Raphson迭代方法分别求解出目标波浪中一阶... 详细信息

基于二阶波势流理论,建立了一个非线性不规则波浪二阶分离模型.通过求解频域内一、二阶成分之间的传递函数,建立起二阶项求解关系式,将二阶项变换到与一阶项同一个傅里叶频域空间,采用Newton-Raphson迭代方法分别求解出目标波浪中一阶、二阶和频与二阶差频.利用所建立模型分别对规则波和二阶非线性不规则波进行了数值验证,并对波浪非线性的影响进行了分析,典型数值计算结果表明模型是有效的.

关键词：非线性不规则波二阶分离 Newton—Raphson迭代

The Economics of Competing Water Uses under a FERC Licensing Agreement: Estimation of Property Value, Recreation, and Hydroelectric Impacts

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Journal of Water Resource and Protection 2024年第6期16卷 414-428页

作者： Matthew bingham Jason Kinnell Veritas Economics Cary USA

Reservoirs provide a variety of services with economic values across multiple sectors. As demands for reservoir services continue to grow and precipitation patterns evolve, it becomes ever more important to consider the integrated suite of values and tradeoffs that attend changes in water uses and availability. Section 316 (b) of the Clean Water Act requires that owners of certain water cooled power plants evaluate technologies and operational measures that can reduce their impacts to aquatic organisms. The studies must discuss the social costs and benefits of alternative technologies including cooling towers (79 Fed. Reg. 158, 48300 - 48439). Cooling towers achieve their effect through evaporation. This manuscript estimates the property value, recreation, and hydroelectric generation impacts that could result from the evaporative water loss associated with installing cooling towers at the McGuire Nuclear Generating Station (McGuire) located on Lake Norman, North Carolina. Although this study specifically evaluates the effects of evaporative water loss from cooling towers, its methods are applicable to estimating the economic benefits and costs of a new water user or reduced water input in any complex reservoir system that supports steam electric generation, hydroelectric generation, residential properties, recreation, irrigation, and municipal water use.

关键词： Property Value FERC Hydroelectric Recreation Water Levels