EFFECT OF SUSPENDED PARTICLE ON STABILITY OF INTERFACE OF MOVING TWO-PHASE JET

ＮＯＭＥＮＣＬＡＴＵＲＥαｓｐａｒｔｉｃｌｅｖｏｌｕｍｅｆｒａｃｔｉｏｎｕｇｉｎｓｔａｎｔａｎｅｏｕｓｇａｓｖｅｌｏｃｉｔｙｖｅｃｔｏｒｕｓｉｎｓｔａｎｔａｎｅｏｕｓｐａｒｔｉｃｌｅｖｅｌｏｃｉｔｙｖｅｃｔｏｒＵｍｅａｎａｘｉａｌｖｅｌｏｃｉｔｙｏｆ...     

CHAOTIC HYDRODYNAMICS IN HORIZONTAL GAS-LIQUID BUBBLY FLOW

ＮＯＭＥＮＣＬＡＴＵＲＥｄ———ｅｍｂｅｄｄｉｎｇｄｉｍｅｎｓｉｏｎ ,ｄｉｍｅｎｓｉｏｎｌｅｓｓＣｄ(ｒ)———ｃｏｒｒｅｌａｔｉｏｎｓｕｍ ,ｄｉｍｅｎｓｉｏｎｌｅｓｓＮ———ｎｕｍｂｅｒｏｆｐａｉｒｓｏｆｐｏｉｎｔｓｏｎｔｈｅｒｅｃｏｎ ｓｔｒｕｃｔｅｄａｔｔｒａｃｔｏｒ,ｄｉｍｅｎｓｉｏｎｌｅｓｓｒ———ｓｃａｌｉｎｇｄｉｓｔａｎｃｅ ,ｄｉｍｅｎｓｉｏｎｌｅｓｓＤｃ ———ｃｏｒｒｅｌａｔｉｏｎｄｉｍｅｎｓｉｏｎ ,ｄｉｍｅｎｓｉｏｎｌｅｓｓＫ———Ｋｏｌｍｏｇｏｒｏｖｅｎｔｒｏｐｙ ,ｂｉｔｓ/ｓＲ…     

CHARACTERISTICS OF MICROBIAL TRANSFUSION IN POROUS MEDIUM AND ITS THEORETICAL INVESTIGATION

ＮＯＭＥＮＣＬＡＴＵＲＥＣｍｍ ——ｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎａｔａｃｅｒｔａｉｎｔｉｍｅ ,Ｃｅｌｌ/ｍＬＣｍｆ ——ｔｈｅｃｈａｎｇｅｏｆｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎａｆｔｅｒｍｉｃｒｏｂｅｓａｒｅａｄｓｏｒｂｅｄＤ′——ｔｈｅｃｏｎｖｅｃｔｉｏｎ ｄｉｆｆｕｓｉｏｎｃｏｅｆｆｉｃｉｅｎｔ,ｃｍ2 /ｓＶ——ｔｈｅｆｌｕｉｄ’ｓａｃｔｕａｌｖｉｓｃｏｓｉｔｙ ,ｃｍ/ｓＣｚｍ ———ｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎｏｆｔｈｅｉｎｊｅｃｔｅｄｍｉｃｒｏ ｂｉａｌＣｏ ———ｔｈｅｃｏｎｃｎｅｔｒａｔ…     

ON THE HIGH PRECISION ADAPTIVE OPEN BOUNDARY CONDITIONS FOR TRANSIENT WAVES

ＯＮＴＨＥＨＩＧＨＰＲＥＣＩＳＩＯＮＡＤＡＰＴＩＶＥＯＰＥＮＢＯＵＮＤＡＲＹＣＯＮＤＩＴＩＯＮＳＦＯＲＴＲＡＮＳＩＥＮＴＷＡＶＥＳ￥ＺｏｕＧｕａｎｇ－ｙｕａｎ（Ｄｅｐｔ．ｏｆＭｅｃｈａｎｉｃｓａｎｄＥｎｇｉｎｅｅｒｉｎｇＳｃｉｅｎｃｅｓ，Ｐｅｋｉｎｇ...     

EVOLUTION EQUATIONS FOR NONLINEAR WAVES IN A THREELAYER FLUID MODEL

ＥＶＯＬＵＴＩＯＮＥＱＵＡＴＩＯＮＳＦＯＲＮＯＮＬＩＮＥＡＲＷＡＶＥＳＩＮＡＴＨＲＥＥＬＡＹＥＲＦＬＵＩＤＭＯＤＥＬ￥ＺｈｕＹｏｎｇ（ＳｈａｎｇｈａｉＩｎｓｔｉｔｕｔｅｏｆＡｐｐｌｉｅｄＭａｔｈｅｍａｔｉｃｓａｎｄＭｅｃｈａｎｉｃｓ，Ｓｈａｎｇｈａｉ...     

APPLICATION OF A NEURAL NETWORK PREDICTOR/CONTROLLER TO DYNAMIC POSITIONING OF FLOATING STRUCTURES

ＮＯＭＥＮＣＬＡＴＵＲＥＡｊ ———ａｖｅｃｔｏｒｏｆｌｅｎｇｔｈＮｗｈｏｓｅｅｌｅｍｅｎｔｓａｒｅｒａｎｄｏｍｎｕｍｂｅｒｓ.ｂｊ ———ｒａｎｄｏｍｎｕｍｂｅｒ .ｇｍ ———ｓｑｕａｓｈｉｎｇｆｕｎｃｔｉｏｎ .Ｉｚ ———ｍａｓｓｍｏｍｅｎｔｏｆｉｎｅｒｔｉａｌａｂｏｕｔｔｈｅｚ ａｘｉｓ .Ｉ———ｔｈｅｔｏｔａｌｎｕｍｂｅｒｏｆｌａｙｅｒｓ .ＯＩｍ(ｔ)———ｔｈｅｓｉｇｎａｌｃｏｍｉｎｇｏｕｔｆｒｏｍｔｈｅｍｔｈｎｏｄｅｉｎｔｈｅｏｕｔｐｕｔｌａｙｅｒ .Ｍｉ ———ｔｈｅｎｕｍｂｅｒｏｆｎｏｄｅ…     

EXPERIMENTAL INVESTIGATION ON THE FLOW THROUGH HANGED-PLATE OF THE TWO-STOREY INTAKE

ＮＯＭＥＮＣＬＡＴＵＲＥＡ ,Ｂ　ｆｌｏｗｐａｔｔｅｒｎＣａ,Ｃｂ 　ｅｘｐｅｒｉｍｅｎｔａｌｃｏｅｆｆｉｃｉｅｎｔＣｆ 　ｐｒｅｓｓｕｒｅｃｏｅｆｆｉｃｉｅｎｔＤ0 　ｔｈｉｃｋｎｅｓｓｏｆｈａｎｇｅｄ ｐｌａｔｅＦｒ0 　ｔｈｅｆｒｏｕｄｅｎｕｍｂｌｅｏｆｕｐ     

LATTICE BOLTZMANN SCHEME TO SIMULATE TWO-DIMENSIONAL FLUID TRANSIENTS

ＮＯＭＥＮＣＬＡＴＵＲＥｐα ———ｐｒｅｓｓｕｒｅｄｉｓｔｒｉｂｕｔｉｏｎｆｕｎｃｔｉｏｎｐ(0 )α ———ｅｑｕｉｌｉｂｒｉｕｍｄｉｓｔｒｉｂｕｔｉｏｎｆｕｎｃｔｉｏｎｅα———ｌｏｃａｌｐａｒｔｉｃｌｅｓｔｒｅａｍｖｅｌｏｃｉｔｙｒ———ｌｏｃａｔｉｏｎｏｆｃｏｍｐｕｔａｔｉｏｎａｌｇｒｉｄｎｏｄｅδｔ ———ｔｉｍｅｉｎｃｒｅｍｅｎｔτ———ｔｈｅＢＧＫｒｅｌａｘａｔｉｏｎｐａｒａｍｅｔｅｒα———ｉｎｄｅｘｏｆｐａｒｔｉｃｌｅｓｔｒｅａｍｄｉｒｅｃｔｉｏｎｂ———ｔｈｅｎｕｍｂｅｒｏｆｐａ…     

黄河明珠三门峡水库

黄河明珠三门峡水库＊ＡＰＥＡＲＬＯＮＴＨＥＹＥＬＬＯＷＲＩＶＥＲ——ＳＡＮＭＥＮＸＩＡＲＥＳＥＲＶＩＯＲ三门峡水利枢纽管理局ＡｄｍｉｎｉｓｔｒａｔｉｏｎｏｆＳａｎｍｅｎｘｉａＫｅｙＷａｔｅｒＣｏｎｓｅｒｖａｎｃｙＰｒｏｊｅｃｔ＊到稿时间：１９９６－０...     

INTERACTION OF VORTICES WITH A PROGRESSIVE SURFACE WAVE

ＩＮＴＥＲＡＣＴＩＯＮＯＦＶＯＲＴＩＣＥＳＷＩＴＨＡＰＲＯＧＲＥＳＳＩＶＥＳＵＲＦＡＣＥＷＡＶＥＷａｎｇＬｉｎ－ｌｉｎ；ＭａＨｕｔ－ｙａｎｇ（ＧｒａｄｕａｔｅＳｃｕｄｏｆＡｃａｄｅｍｉｃａＳｉｎｉｃａＢｅｉｊｉｎｇ１０００３９Ｐ．Ｒ．Ｃｈｉｎａ）Ａｂ...     

Physical and numerical modeling of swirling flow in a scroll vortex intake

Scroll vortex intakes are hydraulic structures commonly used in water supply, drainage and sewerage systems. Water flows into the intake via an eccentric approach channel and a vortex chamber imparts swirl to the flow, leading to a stable air core vortex along the dropshaft. Although much effort has been devoted to investigate the scroll vortex flow, yet the understanding on its hydraulic characteristics is still far from complete due to a lack of detailed velocity field measurements. This paper presents the first comprehensive measurement of the three-dimensional (3D) flow field of a scroll vortex intake using non-intrusive Laser Doppler Anemometry (LDA). A validated 3D Computational Fluid Dynamics (CFD) model with the Volume-Of-Fluid (VOF) method is developed for interpreting the measurement. It is found that the vortex flow in the scroll chamber resembles a free vortex and the circulation is approximately equal to that at the chamber inlet, with a thin bottom boundary layer. The vortex flow at the bellmouth outlet possesses a circulation constant smaller than that in the chamber, and its vertical velocity component is approximately constant across the flow thickness.     

3-D numerical investigation of the wall-bounded concentric annulus flow around a cylindrical body with a special array of cylinders

Concentric annulus flow around a combinational cylindrical body with a special array of cylinders at five high Reynolds numbers is investigated numerically using Fluent 6.3.26 in this paper. The numerical results show a good agreement with the experimental data in regard to the axial velocity of the flow. This study focuses on the flow structure and the hydrodynamic characteristics based on the velocity distribution, the pressure distribution, streamlines and vectors under 1-D, 2-D and 3-D conditions. Meanwhile, some global parameters including the pressure coefficient, the drag coefficient and the lift coefficient are analyzed. Numerical results show that the high velocity region and the reverse wake zone with low velocity exist in some spaces due to the disturbance of the cylindrical body. Negative pressures appear in some regions. Neither a wide area vortex nor the vortex shedding appears in the wall-bounded domain. The drag along the axial direction is the main force acting on the cylindrical body in the pipe domain. The annulus flow around the cylindrical body is analyzed to reveal the hydrodynamic characteristics of the complex turbulent concentric annulus flow field due to the multi-effects in the pipeline.     

高水头混流式水轮机减负荷瞬态流动特性研究

为了平衡和补偿间歇性可再生能源不定时并网对电网的不利冲击,水轮机不得不频繁地经历减负荷瞬态工况转换过程,从而诱发水轮机内部不稳定的压力脉动及涡流结构。基于多面体网格及动网格技术,开展了高水头混流式水轮机导叶关闭减负荷过程水轮机特征参数响应、压力脉动及涡流演化特性的数值模拟工作。研究发现,采用压力边界条件获得的水轮机水头与试验结果吻合较好,流量结果可信度高。负荷变化过程中,无叶区压力脉动相对变化趋势与导叶运动规律一致,且幅值变化不大。导叶开始及停止运动,引起尾水管内的压力信号发生突变,并逐渐形成低频周期性压力脉动。涡带运动诱发的不稳定压力脉动,是转轮轴向水推力形成的主要原因。在导叶闭合过程中,强度较小的轴对称涡带首先沿轴向和径向拉伸,随后沿轴向收缩。导叶停止运动进入部分负荷工况,直涡结构进一步收缩,演变为细长状双螺旋结构,最后双螺旋涡结构合并成强度较高的单一螺旋状涡带。此外,水轮机负荷的减小使尾水管内出现回流,漩涡运动等不稳定现象。     

螺旋侧板截面形状对Spar平台涡激运动的影响研究

处于深水中的Spar平台两侧不断产生周期性漩涡脱落,极易诱发涡激运动,缩短平台疲劳寿命。为探究不同截面形状螺旋侧板对漂浮式风力机Spar平台涡激运动的影响,采用大涡模拟(LES)方法,对亚临界雷诺数流动状态下附加不同截面形状螺旋侧板的平台进行研究,并与光滑平台进行对比,分析其水动力系数及尾涡发放特点。研究表明:螺旋侧板在有效抑制平台升力系数的同时,还会增加阻力系数,圆形截面侧板对平台升力系数的降幅最大,阻力系数增幅最小;螺旋侧板的存在使漩涡脱落频率整体减小,从单一主频发放变为主频和次频发放;圆形截面侧板的漩涡脱落点距离平台最远,发放最为迟缓;在研究范围内,发现圆形截面侧板抑涡效果最佳。     

STUDY OF VORTEX CHARACTERISTICS OF THE FLOW AROUND A HORIZONTAL CIRCULAR CYLINDER AT VARIOUS GAP-RATIOS IN THE CROSS-FLOW

1. INTRODUCTION The flow around a horizontal circular cylinder near a plane boundary (fixed wall) is of great significance in Hydrodynamics. For instance, sewagepipelines in water body of rivers in environmental engineering, conveying pipelines and optica…     

三维圆柱绕流数值模拟湍流方法的选择

研究湍流模拟方法对三维圆柱绕流数值模拟精度的影响,分别采用雷诺平均法（RANS）中的κ-ω模型、SST模型以及大涡模拟法（LES）对亚临界区内雷诺数Re=3 900时的三维圆柱绕流进行数值计算,分析了圆柱体表面的受力、圆柱后流场时均速度特性与瞬时涡量分布情况。结果表明,当流体流过圆柱表面时,圆柱表面出现的与流速方向相反的负压力差区域使流体从圆柱表面分离,引起了不稳定的周期性交替脱落的湍流涡泄,从而在圆柱表面产生周期性波动的升力,同时在圆柱后近流场区域形成回流区。研究还发现,LES法对圆柱体的受力以及流场时均速度特性的模拟效果要优于κ-ω模型与SST模型;相较于前人利用浸入边界法得到的模拟结果,LES法的模拟精度也有了较大提升;同样,通过对瞬时流场涡量等值线图的分析,并与已有的模拟结果进行对比,发现LES法不但可以从整体上表现出漩涡的周期性脱落,而且对流场中不同位置的、复杂的小尺度湍流涡泄也描述得非常细致,得到的自由分离剪切层长度与湍流涡泄的卷曲度更符合湍流涡泄的特征。所以,在亚临界区,LES法对湍流的模拟效果相对较好。     

明渠柱体上游马蹄涡的运动学特征研究

马蹄涡是水下柱体结构周围床面冲刷的主要动力。为掌握马蹄涡的运动学特征,引入了基于旋转强度的马蹄涡识别方法,提出了基于椭圆涡拟合的马蹄涡特征提取方法,其中,椭圆涡由Oseen涡和倾斜单向剪切流叠加而成。基于上述方法,通过开展明渠圆柱绕流PIV实验,对柱体上游对称面时均流场中马蹄涡的运动学特征进行了研究。结果表明,在柱体雷诺数大于104的紊流柱体绕流中,马蹄涡上游的流动分离点随柱体雷诺数的增大而缓慢向下游移动,但马蹄涡的位置保持不变,涡中心距柱体中轴约0.67D(D为柱体直径或宽度),距床面约0.06D;随着柱体雷诺数的增大,马蹄涡的半径不变而强度增加,使得马蹄涡作用于床面的剪切应力增大。研究结果建立了客观提取马蹄涡运动学特征的数学方法,得到了流动分离点、马蹄涡位置等运动学特征随水流条件的变化规律,揭示了明渠柱体绕流与其它流动中柱体绕流的差异,初步构建了马蹄涡的动力作用概念模型。     

螺旋涡丝的运动问题

螺旋涡丝是实际流动中的一种重要流态，螺旋桨的尾迹，三维绕流物体的尾涡构成等都有这样的涡系存在。螺旋涡丝的运动内容包含两部分，第一部分是它诱导的速度场，特别是对自身诱导的速度，第二部分是螺旋涡丝的稳定性，但必须以第一部分为基础。本文具体推导螺旋涡丝对涡心一点的诱导速度公式，对各种螺距算出具体数值结果     

Numerical investigation of the concentric annulus flow around a cylindrical body with contrasted effecting factors

This paper studies the wall-bounded flow around a cylindrical at a high Reynolds numbers body in a determined computational domain, with simulations of the 3-D, turbulent concentric annulus flow in a straight pipe. Numerical results show that a reversing zone, appearing as a tongue zone with nested velocities higher than the surrounding area, exists behind the cylindrical body. The annulus space is a region of high velocity and low pressure. The zero velocity, of combined the X- velocity and the Y- velocity, exists in the cross sections and no vortex shedding is formed behind the attaching cylinders. Among all investigated effecting factors, the diameters of the attaching and the main cylinders affect the wake feature behind the cylindrical body while the main cylinder length does not affect the distribution tendency of the flow field. The diameters of the main cylinder and the pipe affect the pressure values and the distribution tendencies on the main cylinder surface. Obviously, the increase of the pipe diameter reduces the drag coefficient of the cylindrical body and the increase of the diameter of the main cylinder increases the drag coefficient greatly. The numerical investigation of the concentric annulus flow provides foundations for further improvements of the intricate flow studies.     

应用PIV进行二维后向台阶流流动特性的研究(1)二维后向台阶流的旋涡结构的研究

利用PIV技术，对二维后向台阶定常流的瞬态速度场进行了测量，得到层流至湍流情况下定常流流场中旋涡的生成、发展和演化的现象和规律。本文分析了各种情况下旋涡结构特点、讨论了与时均流场和自由剪切层的区别，还给出了二维后向台阶流的拓扑结构。