黄河下游花园口—孙口河段水沙运动仿真模型开发研究

黄河下游洪水演进受滩槽冲淤、生产堤状况与滩地调蓄作用的影响非常显著．花园口～孙口河段水沙运动仿真模型以二维不恒定流与不平衡输沙理论为基础，采用无结构不规则网格，分段建模，联接运行，能较好适应河势的变化．模型具备动态图象显示和人机对话功能，可在计算中较好模拟生产堤溃决或抢险堵口加高等现象．模型对滩槽冲淤具有一定的自调节的能力，增强了模型对黄河来水来沙变幅大的适应能力．模型以“８２８”与“９６８”两场洪水的实测资料作了验证，结果吻合良好     

CONJUGATE FLOWS OVER A STEP IN A THREE-LAYER FLUIDONJU

The conjugate flows over a step with the height h0, which might be positive or negative, was studied in a three-layer fluid and the coupled nonlinear equations were derived, with which the effects of varying height h0 on the existence and evolution of conjugate flows were examined. It is concluded that the conjugate flow is sharply sensitive to the thickness of fluid layers and its characteristics alters remarkably due to the existence of the step. As the flow climbs up a step (h0＞0), the conjugate flow with a convex lower interface and a concave upper interface is allowed to appear, while the flow with the concave lower interface or the simultaneous concave interfaces will be depressed. As the flow goes down a step (i.e., h0＜0), on most occasions only one kind of conjugate flow could exist, which prossesses the form with the simultaneous convex interfaces and will disappear rapidly with the increase of the step depth.     

A LATTICE BOLTZMANN METHOD FOR SIMULATION OF A THREE- DIMENSIONAL DROP IMPACT ON A LIQUID FILM

A single-phase free surface tracking model based on the Lattice Boltzmann Method （LBM）, which has capability of simulating liquid-gas system with the assumption that the gas phase has only negligible influence on the liquid phase, is utilized to simulate the flow of a drop impacting on a liquid film. Three typical outcomes in the flows, i.e., deposition, crown and splash, which have been observed in the previous experiments, are obtained in the present three dimensional numerical simulations. The numerical results are consistent with the experimental and analytical results available.     

FLOW AROUND A CIRCULAR CYLINDER USING A FINITE-VOLUME TVD SCHEME BASED ON A VECTOR TRANSFORMATION APPROACH

Flows around a circular cylinder displaying an unsteady vortex shedding process at the Reynolds numbers of 1000,3900 and 1×104 are studied using a finite-volume Total Variation Diminishing(TVD) scheme for solving the Unsteady Reynolds-Averaged Navier-Stokes(URANS) equations.An Elemental Velocity Vector Transformation(EVVT) approach is proposed for the local normal and tangential velocity transformation at the interfaces of main and satellite elements.The presented method is validated by comparing with the available experimental data and numerical results.It is shown that the two-dimensional TVD finite volume method with the Renormalization Group(RNG) turbulence model can be used to determine hydrodynamic forces and captures vortex shedding characteristics very well.     

EVALUATION OF HFAM ON A FLOW OVER A BACKWARD－FACING STEP

ＥＶＡＬＵＡＴＩＯＮ　ＯＦ　ＨＦＡＭ　ＯＮ　Ａ　ＦＬＯＷ　ＯＶＥＲ　Ａ　ＢＡＣＫＷＡＲＤ－ＦＡＣＩＮＧ　ＳＴＥＰＥＶＡＬＵＡＴＩＯＮＯＦＨＦＡＭＯＮＡＦＬＯＷＯＶＥＲＡＢＡＣＫＷＡＲＤ－ＦＡＣＩＮＧＳＴＥＰ￥ＺｈａｎｇＸｉａｏ－ｙｕａｎ；ＬｉＷｅｉ（...     

HAGEN POISEUILLE FLOW OF A GRANULAR MATERIAL IN A CYLINDER

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｙｅａｒｓ ,ｓｔｕｄｙｉｎｇｔｈｅｍｏｔｉｏｎｏｆｆｉｎｅｇｒａｎｕ ｌａｒｍａｔｅｒｉａｌｓｉｓａｎｅｗｔｏｐｉｃｉｎｆｌｕｉｄｍｅｃｈａｎｉｃｓ.Ａｌｔｈｏｕｇｈｇｒａｎｕｌａｒｍａｔｅｒｉａｌｓｄｏｅｓｎｏｔｂｅｌｏｎｇｔｏｒｅａｌｆｌｕｉｄ ,ｔｈｅｍｅｔｈｏｄｓｏｆｓｔｕｄｙｉｎｇ ｇｒａｎｕｌａｒｍａｔｅｒｉａｌｓａｒｅｓｉｍｉｌａｒｔｏｔｈｏｓｅｏｆｆｌｕｉｄ ｓｔｕｄｙｉｎｇ .Ｓｏｍａｎｙｍｅｔｈｏｄｓｏｆｆｌｕｉｄ ｓｔｕｄｙｉｎｇｈａｖｅ…     

A SEPARATED－LAYER FINITE ANALYTIC METHOD FOR NUMERICAL SIMULATION OF A THREE－DIMENSIONAL VISCOUS FLOW FIELD AROUND A SHIP STERN

ＡＳＥＰＡＲＡＴＥＤ－ＬＡＹＥＲＦＩＮＩＴＥＡＮＡＬＹＴＩＣＭＥＴＨＯＤＦＯＲＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＡＴＨＲＥＥ－ＤＩＭＥＮＳＩＯＮＡＬＶＩＳＣＯＵＳＦＬＯＷＦＩＥＬＤＡＲＯＵＮＤＡＳＨＩＰＳＴＥＲＮＬｉＴｉｎｇ－ｑｉｕ；Ｍｉａｏ...     

建立现代水资源管理系统初探

水资源管理工作正逐步进入一个对水的资源管理和需水定向管理的新阶段,管理的内容有了很大扩展,必须尽快建立一个与管理内容和形式相适应的现代水资源管理体系.明确现代水资源管理的目标、内容和原则,研究确立建立现代水资源管理系统的对策措施,全面提高水资源管理水平.     

A/A/O工艺调试运行体会

根据实际工程调试遇到的问题,从理论和实践上对A/A/O 工艺调试及运行模式作了探讨,结合各污水厂水质、水量特点和不同的处理设施,对A/A/O 工艺运行中各工艺控制参数进行了系统分析和有效控制,并就调试过程遇到的问题谈几点体会,为新建和将建污水厂的运行管理人员提供参考.     

INTERACTION OF A FLOATING ELLIPTIC CYLINDER WITH A VIBRATING CIRCULAR CYLINDER

1. INTRODUCTION The hydrodynamic interaction between two submerged “non-circular’ bodies is of significant importance from both practical and theoretical points of view. In general, a detailed study of this problem is very difficult. Even in an ideal fl…     

SECOND ORDER TRANSIENT WAVES AROUND A VERTICAL CYLINDER IN A TANK

ＳＥＣＯＮＤＯＲＤＥＲＴＲＡＮＳＩＥＮＴＷＡＶＥＳＡＲＯＵＮＤＡＶＥＲＴＩＣＡＬＣＹＬＩＮＤＥＲＩＮＡＴＡＮＫ￥Ｑ．Ｗ．Ｍａ，Ｇ．Ｘ．Ｗｕ（ＤｅｐａｒｔｍｅｎｔｏｆＭｅｃｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎｇＵｎｉｖｅｒｓｉｔｙＣｏｌｌｅｇｅＬｏｎｄｏ...     

A STUDY ON CAVITATION AND CAVITATION DAMAGE IN A CAVITATION TUNNEL

The test results on cavitation and cavitation damage in a cavitation tunnel arepresented in this paper.The cavitator in the shape of 60 deg.symmetric wedge was mounted in-to the inlet of the working section of 20×40×170mm~3 in size.The velocities ranged from8.5m/s to 13.5m/s.At first,the flow structure around the wedge was revealed by a LaserDoppler Velocimetry.Then,the fluctuating pressure signals induced by vortex cavitation werepicked up by a micro-transducer.Cavitation erosion tests were just done at the velocity of13.5m/s.The aim of this work is to investigate the relation between cavitation inception andflow structure and to explore the dependence of cavitation damage on cavitation intensity.Thecavitation intensity which is defined as the power density per unit time can be regarded as the in-put of the test system.The intensity of cavitation damage is supposed to be the consumed powerdensity per unit time and considered as the output of the system of test,The ratio of the output tothe input is as the efficiency of the test system.The test results also show that the output is verysmall in quantity as compared with the input.     

HYDRODYNAMIC STUDY ON A PECTORAL FIN ROWING MODEL OF A FISH

Fish pectoral fin movement involves primarily a drag-based and a lift-based mechanisms to produce thrust. A numerical study on a pectoral fin rowing propulsion model based on the drag-based mechanism is presented in this article. The propulsive mechanism of the pectoral fin rowing model is related with the voriticity and pressure in the flow field. The relationship between the thrust and kinematic parameters and the wake-captured problem are analyzed. It is shown that a high thrust is produced in the power stroke, mainly due to the backward translation acceleration, the anticlockwise angular acceleration and the absence of stall in the uniform translation. Moreover, the flow control mechanism and the effect of dynamic flexible deformation are further analyzed. To properly choose controllable factors and adopt an appropriate dynamic deformation can improve the propulsive performance.     

THE WAVE-MAKING CHARACTERISTICS OF A MOVING BODY IN A TWO-LAYER FLUID

The Wave-making characteristics of a moving body in a two-layer fluid with free surface is investigated numerically and experimentally. The numerical analysis is based on the modified layered boundary integral equation system. The wave characteristics on the free surface and interface generated by a moving sphere and an ellipsoid is numerically simulated in both finite depth and infinite depth of lower layer model. The numerical results of the sphere are compared with the analytical results for a dipole with the same velocity in a two-layer fluid of finite depth. The dependence of the wave systems and structures on the characteristic quantities is discussed. Three kinds of measurement techniques are used in model experiments on the internal waves generated by a sphere advancing in a two-layer fluid. The effects of the varying velocity and stratification on the wavelength, wave amplitudes and the maximum half angles of internal waves are analyzed qualitatively.