NUMERICAL SIMULATION OF SCALE EFFECT ON SHIP STERN FLOW AND HYDRODYNAMIC PERFORMANCE

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＳＣＡＬＥＥＦＦＥＣＴＯＮＳＨＩＰＳＴＥＲＮＦＬＯＷＡＮＤＨＹＤＲＯＤＹＮＡＭＩＣＰＥＲＦＯＲＭＡＮＣＥ￥ＧａｏＱｉｕ－ｘｉｎ；ＺｈｏｕＬｉａｒ－ｄｉ（ＣｈｉｎａＳｈｉｐＳｃｉｅｎｔｉｆｉｃＲｅｓｅａｒｃｈＣ...     

THE INFLUENCE OF THE SECONDARY NORMAL STRESS DIFFERENCE OF VISCOELASTIC FLUID ON ECCENTRIC CAPSULE FLOW

ＴＨＥＩＮＦＬＵＥＮＣＥＯＦＴＨＥＳＥＣＯＮＤＡＲＹＮＯＲＭＡＬＳＴＲＥＳＳＤＩＦＦＥＲＥＮＣＥＯＦＶＩＳＣＯＥＬＡＳＴＩＣＦＬＵＩＤＯＮＥＣＣＥＮＴＲＩＣＣＡＰＳＵＬＥＦＬＯＷ￥ＰａｎＤａ－ｌｉｎ（ＧｕａｎｇｄｏｎｇＩｎｓｔｉｔｕｔｅｏｆｏｆＴｅｃ...     

NUMERICAL SIMULATION AND EXPERIMENTAL STUDY OF THE FLOW FIELD AROUND A CIRCULAR CYLINDRICAL ARTIFICIAL ISLAND UNDER THE ACTION OF WAVES AND VISCOUS CURRENT

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＡＮＤＥＸＰＥＲＩＭＥＮＴＡＬＳＴＵＤＹＯＦＴＨＥＦＬＯＷＦＩＥＬＤＡＲＯＵＮＤＡＣＩＲＣＵＬＡＲＣＹＬＩＮＤＲＩＣＡＬＡＲＴＩＦＩＣＩＡＬＩＳＬＡＮＤＵＮＤＥＲＴＨＥＡＣＴＩＯＮＯＦＷＡＶＥＳＡＮＤＶＩＳＣＯＵ...     

NUMERICAL SIMULATION OF THE EFFECT OF FILLET FORMS ON APPENDAGE－BODY JUNCTION FLOW

ＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＴＨＥＥＦＦＥＣＴＯＦＦＩＬＬＥＴＦＯＲＭＳＯＮＡＰＰＥＮＤＡＧＥ－ＢＯＤＹＪＵＮＣＴＩＯＮＦＬＯＷＬｉＤｉｎｇ；ＺｈｏｕＬｉａｎ－ｄｉ（ＣｈｉｎａＳｈｉｐＳｃｉｅｎｔｉｆｉｃＲｅｓｅａｒｃｈＣｅｎｔｅｒＰ．...     

NUMERICAL COMPUTATION OF THE DIFFUSION OF THE CONTAMINANTS AND THE FLOW FIELD OF SKEW DISCHARGES INTO A CHANNEL

ＮＵＭＥＲＩＣＡＬ　ＣＯＭＰＵＴＡＴＩＯＮ　ＯＦ　ＴＨＥ　ＤＩＦＦＵＳＩＯＮ　ＯＦ　ＴＨＥ　ＣＯＮＴＡＭＩＮＡＮＴＳ　ＡＮＤ　ＴＨＥ　ＦＬＯＷ　ＦＩＥＬＤ　ＯＦ　ＳＫＥＷ　ＤＩＳＣＨＡＲＧＥＳ　ＩＮＴＯ　Ａ　ＣＨＡＮＮＥＬＮＵＭＥＲＩＣＡＬＣＯＭＰＵ...     

RANDOM CHARACTERISTICS OF FLOW FLUCTUATING PRESSURE AND DYNAMIC RESPONSE ON THE SHAFT SPILLWAY

ＲＡＮＤＯＭＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＦＬＯＷＦＬＵＣＴＵＡＴＩＮＧＰＲＥＳＳＵＲＥＡＮＤＤＹＮＡＭＩＣＲＥＳＰＯＮＳＥＯＮＴＨＥＳＨＡＦＴＳＰＩＬＬＷＡＹＣｕｉＬｉ（ＤａｌｉａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｄａｌｉａｎ１１...     

THE TURBULENCE CHARACTERISITICS OF OPEN CHANNEL FLOW

ＴＨＥ　ＴＵＲＢＵＬＥＮＣＥ　ＣＨＡＲＡＣＴＥＲＩＳＩＴＩＣＳ　ＯＦ　ＯＰＥＮ　ＣＨＡＮＮＥＬ　ＦＬＯＷＴＨＥＴＵＲＢＵＬＥＮＣＥＣＨＡＲＡＣＴＥＲＩＳＩＴＩＣＳＯＦＯＰＥＮＣＨＡＮＮＥＬＦＬＯＷ￥ＷａｎｇＸｉｎｇ－ｋｕｉ（Ｄｅｐａｒｔ．ｏｆＨｙｄｒ...     

NUMERICAL PREDICTION OF THREE DIMENSIONAL HIGHLYTURBULENT FLOW WITH FREE SURFACES

ＮＵＭＥＲＩＣＡＬＰＲＥＤＩＣＴＩＯＮＯＦＴＨＲＥＥＤＩＭＥＮＳＩＯＮＡＬＨＩＧＨＬＹＴＵＲＢＵＬＥＮＴＦＬＯＷＷＩＴＨＦＲＥＥＳＵＲＦＡＣＥＳ￥ＭａＦｕ－ｘｉ（ＮｏｒｔｈＣｈｉｎａＩｎｓｔｉｔｕｔｅｏｆＷａｔｅｒＣｏｎｓｅｒｖａｎｃｙａｎｄＨｙｄｒ...     

NUMERICAL SIMULATION OF FLOW FOLD OF A RIVER WITH COMPLICATED BOUNDARIES

ＮＵＭＥＲＩＣＡＬ　ＳＩＭＵＬＡＴＩＯＮ　ＯＦ　ＦＬＯＷ　ＦＩＥＬＤ　ＯＦ　Ａ　ＲＩＶＥＲ　ＷＩＴＨ　ＣＯＭＰＬＩＣＡＴＥＤ　ＢＯＵＮＤＡＲＹＳＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＦＬＯＷＦＯＬＤＯＦＡＲＩＶＥＲＷＩＴＨＣＯＭＰＬＩＣＡＴＥＤＢ...     

NUMERICAL SIMULATION OF DISCONTINUOUS FLOW IN CIRCULAR CONDUITS

ＮＵＭＥＲＩＣＡＬ　ＳＩＭＵＬＡＴＩＯＮ　ＯＦ　ＤＩＳＣＯＮＴＩＮＵＯＵＳ　ＦＬＯＷ　ＩＮ　ＣＩＲＣＵＬＡＲ　ＣＯＮＤＵＩＴＳＮＵＭＥＲＩＣＡＬＳＩＭＵＬＡＴＩＯＮＯＦＤＩＳＣＯＮＴＩＮＵＯＵＳＦＬＯＷＩＮＣＩＲＣＵＬＡＲＣＯＮＤＵＩＴＳ￥ＭａｏＺｅ...     

Turbulent heat transfer and pressure loss in a square channel with discrete broken V-rib turbulators

Turbulent periodic flow, heat transfer, friction loss and thermal enhancement characteristics in a three-dimensional horizontal square channel with broken V-ribs(B-VR) are numerically investigated. The computations are based on the finite volume method, and the SIMPLE algorithm with QUICK scheme is implemented. The B-VR were installed on both sides of a plate which was diagonally placed in a square channel to produce longitudinal vortex flows through the tested section. Effects of different open corner ratios( d/ H= 0, 0.01, 0.02, 0.03, 0.04 and 0.05) on heat transfer and pressure loss in the channel and the results of the B-VR are studied. The pitch ratio(PR = p/ H) and blockage ratio(BR = p/ H) of B-VRs were fixed at 1.0 and 0.15, respectively. As compared with the channel without V-rib, the one with B-VRs possessed considerably higher heat transfer and friction loss. It is observed that apart from the rise of Reynolds number, the reduction of the open corner ratios leads to an increase in the Nusselt number and friction factor due to the weaker turbulence and lower resistance to the flow. According to the computational results for B-VRs, the optimum thermal enhancement is found at d/ H= 0.     

分岔管道三维湍流水力特性数值模拟

建立了分岔管道水动力学的计算模型,求解三维贴体坐标系下水流控制方程。计算中采用修正的k-ε湍流模型,应用有限体积法离散方程,物理变量采用同位网格布置,控制体表面上各变量的值用界面动量插值法计算,速度-压力耦合计算采用SIMPLEC算法。本文应用该数值模型模拟了三维弯道水流的水力特性,并与模型试验实测值进行了比较,结果吻合较好。最后应用该数值模型预测了35°分岔管道连接区域三种流动情况的水力特性。     

求解不可压层流的一种全隐数值格式

该文基于SMAC(simplified marker and cell)方法,发展了一种在任意曲线坐标系中求解不可压黏性层流的全隐数值格式。基本方程是以逆变速度为未知变量的动量方程和关于压力修正量的Poisson方程。所有方程离散在MAC交错网格系统中进行。根据构造的全隐数值格式自编程序对一可简化成二维层流的后台阶流场进行计算,通过与已有的实验结果和计算结果进行比较,确认目前的计算结果优于比较的计算结果,和实验结果也相当吻合。为进一步验证该数值格式的可靠性,扩展程序对三维后台阶层流进行计算,结果表明,三维计算结果比二维计算结果更加接近实验结果。     

Numerical analysis of a magnetohydrodynamic duct flow with flow channel insert under a non-uniform magnetic field

This study performs a numerical analysis of three-dimensional liquid metal(LM) magnetohydrodynamic(MHD) flows in a square duct with an FCI in a non-uniform magnetic field. The current study predicts detailed information on flow velocity, Lorentz force, pressure, current and electric potential of MHD duct flows for different Hartmann numbers. Also, the effect of the electric conductivity of FCI on the pressure drop along the main flow direction in a non-uniform magnetic field is examined. The present study investigates the features of LM MHD flows in consideration of the interdependency among the flow variables.     

NUMERICAL INVESTIGATION ON THE AEROELASTIC BEHAVIOR OF AN AIRSHIP WITH HULL-FIN CONFIGURATION

Numerical investigation was conducted on an airship of hull-fin configuration for aerodynamic and aeroelastic characteristics in three-dimensional viscous flows. The mathematical model was built and the corresponding numerical code was developed for the fluid-structure interaction problem. The governing equations of the viscous flow with LL-Low Reynolds modified model were solved by the standard SIMPLE algorithm based on the finite volume method. A fluid-structure coupled method was employed to solve the nonlinear aeroelasticity problem for the airship. The computational results of the viscous flow are in good agreement with the experimental measurements. The simulation on the aeroelastic behavior of the airship in a trimmed flight reveals the effect of structure flexibility on the aerodynamic performance.     

三方柱绕流的大涡模拟及频谱分析

高雷诺数条件下,无论来流是均匀还是非均匀,多方柱绕流情况下方柱受力及尾流的相互干扰都是相当复杂的。为了研究方柱受力及下游尾流的相互干扰,基于大涡模拟紊流模型对后品字等边布置的三方柱绕流进行了数值模拟,数值模拟结果表明,上游两个方柱的阻力系数要明显小于下游方柱,而上游两方柱升力系数远大于下游方柱,且下游方柱的升力系数基本上在零左右振荡,通过频谱分析发现了它们之间的区别。方柱的尾流存在着强烈的非对称相互干扰,且涡有明显的三维性。     

NUMERICAL ANALYSIS OF THE INFLUENCE OF THE TIP CLEARANCE FLOWS ON THE UNSTEADY CAVITATING FLOWS IN A THREE- D IMENSIONAL INDUCER

To clarify the influences of the tip clearance flows on the unsteady cavitating flow,the three-dimensional unsteady cavitating flows through both the two-dimensional cascades and the three-dimensional inducer with and without tip clearance are performed numerically.The governing equations for the compressible fluid flow with the DES turbulence model are employed with the assumption of the isentropic process of liquid phase.The evolution of cavities is represented as the source/sink of vapor phase.The basic equations in the curve linear coordinate are solved by the finite difference method.As the results of the three-dimensional cavitating flows through the two-dimensional cascades,the tip clearance flows from the pressure side to the suction side of the blade produces the tip vortex cavitation,which affects the sheet cavitation on the leading edge of the next blade and enhances the blockage effect near the casing than the flows without tip clearance.On the other hand,in the case of the three-dimensional inducer,the large backflow cavitation is observed around the inlet of the inducer,where the cavities are developed on the casing by the tip clearance flows.The large pressure gradient between the non-cavitating pressure side and the cavitating suction side enhances the tip clearance flows.The calculation considering the tip clearance reproduces the developed cavitation region similar to that of experimental visualizations.Additionally,the backflow cavitation rotates with the speed slower than the rotation speed of the inducer.Then,the rotation of backflow cavitation causes the periodic fluctuation of the outlet pressure greater than that of the inlet pressure.     

三维水动力泥沙输移模型及其在珠江口的应用

为研究河口的泥沙输移规律和最大浑浊带与盐水入侵、咸淡水混合等的关系，本文提出了具有二阶精度、建立在9结点有限单元上的三维水动力及泥沙输移模型，该模型考虑了由水平密度梯度引起的斜压项、引用2．5阶Mellor-Yamada紊流模型耦合计算水流的涡动黏滞性系数与物质的紊动扩散系数。本模型采用破开算子法求解控制方程：用欧拉-拉格朗日法求解水平对流项；用有限元法求解水平扩散项；有限差分法求解垂向扩散项。模型应用于模拟珠江口的泥沙运动，计算域包括整个河口的八大口门，用1998年7月的洪季大潮实测资料进行了潮位、流速及流向、盐度及含沙量等的验证，模型计算结果与实测结果吻合良好。在模型验证的基础上，文中简要讨论了珠江河口的泥沙输移、盐水入侵及最大浑浊带等物理现象。     

Minimal intervention to simulations of shallow-water equations

A minimal intervention (MI) strategy is employed to manage the unphysical oscillations in the classical finite volume (CFV) numerical solution of the shallow-water equations. Only the missing variables on the face of the finite volume are modified for Total Variation Diminishing (TVD). The MI strategy maintains long-term computational stability without compromising the accuracy of the numerical solution. Flux limiters are implemented by imposing downwind weighting factor constraints on the missing variables on a staggered grid as the shallow-water equations are updated by a fourth-order Runge-Kutta scheme. The shock capturing capability of this MI-CFV method is verified by comparing the simulations with the exact solutions. A series of turbulence simulations for sub-critical and super-critical flows demonstrates the long-term numerical stability of the computation scheme developed using the MI strategy.     

Numerical models and theoretical analysis of supercritical bend flow

The flow pattern of supercritical flow in bend channels is complicated due to the shock wave phenomenon, which creates difficulties with regard to research and design of bend channels. Using the spillway of an actual project as an example, a three-dimensional numerical investigation was conducted to simulate the flow in a steep-slope bend based on the renormalization group(RNG) k-ε turbulence flow model and the volume of fluid(VOF) method. The validity of the numerical simulation was demonstrated by comparison between the results of numerical simulation and physical model tests. An optimal scheme of setting vertical vanes in the bend channel is presented. The results of numerical simulation and physical model tests are in agreement, which demonstrates the effectiveness of optimization of vertical vanes and the validity of the three-dimensional numerical simulation. Water depths along both bend walls were analyzed numerically and theoretically. The formula for calculating supercritical water depth along either bend wall was derived, and the critical condition of flow separation from the inner wall was determined.