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FORMATION AND INFLUENCING FACTORS OF FREE SURFACE VORTEX IN A BARREL WITH A CENTRAL ORIFICE AT BOTTOM

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Journal of Hydrodynamics 2009年第2期21卷 238-244页

作者： LI Hai-feng CHEN Hong-xun MA Zheng ZHOU Yi shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 China china Ship Scientific Research Center Wuxi 214082 China

Based on the Navier-Stokes equations with considering the effect of the Coriolis force, the finite volume method was employed to discretize the governing equations, the SIMPLE method was adopted to solve the discretized equations, and the flow field in a barrel with an outlet at the center of the bottom was simulated. The numerical results agree well with the experimental data. From the Lagrangian, the relations among the acceleration, the Coriolis force and the viscosity force were analyzed. The results show that the Coriolis force is the major factor that causes the formation of the vortex. The flow fields in the flume under different incoming flow conditions were numerically simulated using the software Fluent. The numerical simulations show good agreement with the experiments for the shape and position of the vortex.

关键词： free surface vortex Coriolis force numerical simulation

THE MIXED STATE HAMILTONIAN DYNAMIC ELEMENT AND A SEMI-ANALYTICAL SOLUTION FOR THE ANALYSIS OF THICK LAMINATED COMPOSITE PLATES

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Acta Mechanica Solida Sinica 1995年第2期8卷 154-162页

作者： Zou Guiping(shanghai institute of applied mathematics and mechanics,shanghai University,shanghai 200072,china)Tang Limin(Research institute of Engineering mechanics,Dalian Uuiversity of Techuology,Dalian 116024,china) shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 China Research institute of Engineering mechanics Dalian University of Technology Dalian 116024 China

Through introducing the Laplace transformation in the time direction, the mixed state Hamilton canonical equation and a semi-analytical solution are presented for analyzing the dynamic response of laminated composite plates. This method accounts for the separation of variables, the finite element discretization can be employed in the plane of laminar, and the exact solution in the thickness direction is derived by the state space control method. To apply the transfer matrix method, the relational expression at the top and bottom surface is established. So the general solution in transformation space is deduced by the spot method. By the application of inversion of Laplace transformation, the transient displacements and stresses can be derived.

关键词： HAMILTON CANONICAL EQUATION LAMINATED COMPOSITE PLATE

New Exact Solutions to (2+1)-Dimensional Variable Coefficients Broer-Kaup Equations

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Communications in Theoretical Physics 2006年第9期46卷 393-396页

作者： ZHU Jia-Min~(1,2,+) MA Zheng-Yi~(1,2) ~1 Department of Physics, Zhejiang Lishui University, Lishui 323000, china ~2.shanghai institute of applied mathematics and mechanics, shanghai 200072, china Department of Physics Zhejiang Lishui University Lishui 323000 China shanghai institute of applied mathematics and mechanics Shanghai 200072 China

In this paper, using the variable coefficient generalized projected Ricatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. These solutions include Weierstrass function solution, solitary wave solutions, soliton-like solutions and trigonometric function solutions. Among these solutions, some are found for the first time. Because of the three or four arbitrary functions, rich localized excitations can be found.

关键词： variable coefficient generalized projected Ricatti equation method (2+1)-dimensional variable coefficients Broer Kaup equations Weierstrass function solution solitary wave solution trigonometric function solution

EXPERIMENTAL STUDY ON THE VORTEX FORMATION AND ENTRAINMENT CHARACTERISTICS FOR A ROUND TRANSVERSE JET IN SHALLOW WATER

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Journal of Hydrodynamics 2009年第3期21卷 386-393页

作者： FAN Jing-yu ZHANG Yan WANG Dao-zeng shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 China Key Laboratory of Advanced Display and System Applications Ministry of Education and SMIT Center School of Mechatronics Engineering and Automation Shanghai University Shanghai 200072 China

The vortex formation and entrainment characteristics for a round transverse jet in shallow water were experimentally investigated by means of a combination of LIF flow visualization and PIV measurement. A scarf vortex wrapped around the main body of the jet is formed in the near-wall region due to the interaction between the resulting wall jet and sufficiently shallow crossflow, with some more or less unsteady flow properties and with spreading ranges as functions of both the velocity ratio and the water depth within the near field. The entrainment of the ambient crossflow fluid into the jet main body is closely associated with the time-evolving features of the shear layer between the jet and surrounding fluid as well as the induced vortical structures near the wall. In the case of slight impingement upon the wall, the interaction between the jet shear layer and the weak, unstable scarf vortex gives rise to an appreciable local entrainment enhancement, confined in the near-wall region in the vicinity of the stagnation point. While in the case of intense impingement upon the wall, the well-organized and stable scarf vortex gives rise to a greatly enhanced entrainment and a greatly increased lateral spreading rate nearly throughout the overall near field as compared to the conventional wall jet. In addition, the entrainment of the ambient crossflow fluid by the scarf vortex in this case occurs largely on the surface of the unique spiral roller structure by itself due to the presence of smaller and unorganized eddies, and accordingly the scarf vortex is likely to keep its spiral roller structure steadily to a relatively great downstream distance within the near field.

关键词： transverse jet shallow water vortex formation entrainment PIV measurement

LARGE-EDDY SIMULATION OF THREE-DIMENSIONAL VORTICAL STRUCTURES FOR AN IMPINGING TRANSVERSE JET IN THE NEAR REGION

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Journal of Hydrodynamics 2007年第3期19卷 314-321页

作者： FAN Jing-yu ZHANG Yan WANG Dao-zeng shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 China Key Laboratory of Advanced Display and System Applications （shanghai University） Ministry of Education and SMIT Center Shanghai University Shanghai 200072 China Department of applied mechanics Chalmers University of Technology SE-412 96 Gothenburg Sweden shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 China

The three-dimensional vortical structures for an impinging transverse jet in the near region were numerically investigated by means of Large-Eddy Simulation （LES）. The LES results reproduced the skewed jet shear layer vortices close to the jet nozzle and the scarf vortex in the near-wall zone in good agreement with the experimental observations. Different vortical modes in the skewed jet shear layer close to the jet nozzle were identified depending upon the velocity ratio between jet and crossflow, namely changing from an approximately axisymmetric mode to a helical one with the velocity ratios varying from 20 to 8. Moreover, the scarf vortex wrapped around the impinging jet in the near-wall zone showed distinct asymmetry with regard to its bilateral spiral legs within the near region. And the entrainment of the ambient crossflow fluids by the scarf vortex in the near-wall zone was appreciably influenced by its asymmetry and in a large part occurred on the surface of the spiral roller structures in the course of spreading downstream.

关键词： Large-Eddy Simulation (LES) impinging jet crossflow vortical structure entrainment

AN EXPONENTIAL-TYPE WEIGHTED IMPLICIT SCHEME AND ALTERNATING GROUP EXPLICIT ITERATIVE METHOD FOR BURGERS EQUATION

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Journal of Hydrodynamics 2006年第1期18卷 63-69页

作者： FENG Xiu-fang TIAN Zhen-fu DAI Shi-qiang shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 China School of mathematics and Computer Science Ningxia University Yinchuan 750021 China

A new exponential-type weighted implicit difference schcme for solving the Burgers equation was developed and iterated by using the Alternating Group Explicit （AGE） method which has the obvious property of parallelism. The stability of the method was analyzed with linearization procedure. A model problem was numerically solved with the proposed scheme. The results show that the method is superb or to some existing schemes.

关键词： Burgers equation exponential type alternating group explicit method stability

NONLINEAR WAVE INDUCED BY AN ACCELERATING CYLINDRICAL TANK

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Journal of Hydrodynamics 2002年第2期14卷 12-16页

作者： Shi, Xiao-Min Le, Jia-Chun An, Shu-Ping Inst. of Appl. Math. and Mech. Shanghai Univ. Shanghai 200072 China Lab. of Solid Mech. of Ministry Tongji Univ. Shanghai 200092 China

This paper presents a method for solving Lagrangian version of governing equations that allows boundary conditions at the free surface to be satisfied exactly, which is a three-dimensional generalization of a method first put forward by Stoker. Analytical expressions of nonlinear hydrodynamic pressure up to the third order and of free surface displacement up to the fourth order of an accelerating cylindrical tank were obtained. Here only the motions of objects in their early stage after initial impulses was considered. As a justification of the method, the important special case when the ratio of tank diameter to fluid depth tends to infinity was taken as an example, which shows that the linear hydrodynamic pressure obtained agrees completely with Westergaard or von Karman's classical result.

关键词： Boundary conditions Hydrodynamics Nonlinear systems Pressure Surfaces Tanks (containers)

A NEW CONTINUUM TRAFFIC MODEL WITH THE EFFECT OF VISCOSITY

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Journal of Hydrodynamics 2011年第2期23卷 164-169页

作者： SONG Tao LI Xing-li KUANG Hua DONG Li-yun shanghai institute of applied mathematics and mechanics Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Shanghai 200072 China School of applied Science Taiyuan University of Science and Technology Taiyuan 030024 China College of Physics and Technology Guangxi Normal University Guilin 541004 China

Through considering the connection between microscopic car-following model and macroscopic continuum model, a new viscous vehicular flow model is proposed, in which the viscosity coefficient is determined by a more realistic constitutive relationship between averaged reaction time of drivers and the car density. Further analysis indicates that two traffic sound speeds in this viscous model may determine the existence and the stability of traveling wave solutions with an analytical method.

关键词： viscosity continuum traffic model reaction time traffic sound speed traveling wave

LATTICE BOLTZMANN METHOD SIMULATIONS FOR MULTIPHASE FLUIDS WITH REDICH-KWONG EQUATION OF STATE

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Journal of Hydrodynamics 2011年第6期23卷 814-819页

作者： WEI Yi-kun QIAN Yue-hong shanghai institute of applied mathematics and mechanics Shanghai University Shanghai 200072 ShanghaiChina

In this article we state that the compression factor of the Redlich-Kwong Equation Of State （EOS） is smaller than that of van der Waals EOS. The Redlich-Kwong EOS is in better agreement with experimental data on coexistence curves at the critical point than the van der Waals EOS. We implement the Redlich-Kwong EOS in the Lattice Boltzmann Method （LBM） simulations via a pseudo-potential approach. We propose a new force, which can obtain computational stationary and reach larger density ratio. As a result, multi-phase flows with large density ratio （up to 1012 in the stationary case） can be simulated. We perform four numerical simulations, which are respectively related to single liquid droplet, vapor-liquid separation, surface tension and liquid coalescence of two droplets.

关键词： Redlich-Kwong equation of state lattice Bhatager-Gross-Krook models numerical simulations phase transition