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HYDRODYNAMIC CHARACTERISTICS AND OPTIMIZATION DESIGN OF EFFICIENT AXIAL-FLOW BLAST WITH LOW NOISE AND ENERGY SAVING

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Journal of Hydrodynamics 2002年第4期14卷 40-46页

作者： tan soon keat School of Civil and Structural Engineering Nanyang Technological University

Based on the demand on efficient axial-flow blast with low noise and energy saving, a blade was designed through the application of the unequal work distribution principle and the exponential twisted camber was used to shape blades. Then, the hydrodynamic characteristics of blades were studied and the strengths and vibrations of blades and hydro-dynamic noise of blast were analyzed. Furthermore, the software of optimization design of axial-flow blast was developed. Finally, the HMF-T40No.20 axial-flow blast used in large textile conditioner system of cotton spinning industry was designed, which could meet the required total safety and environmental requirements as the corresponding test demonstrates. The study is beneficial to designing axial-flow blast.

关键词： Acoustic noise Design Noise abatement Optimization Software engineering Turbomachine blades

RESEARCH ON STABILITY OF INTERFACE OF JET CONTAINING SUSPENDED SOLID PARTICLES

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Applied Mathematics and Mechanics(English Edition) 2000年第7期21卷 741-746页

作者：周泽宣 tan soon keat 林建忠 Department of Mechanics Zhejiang University Hangzhou P R China School of Civil and Structural Engineering Nanyang Technological University Singapore

The stability equation of interface of two-phase jet and the corresponding particle-gas disturbance velocity ratio equation are derived by means of the phase-coupled model. The stability nares of interface of two-phase jet for different particle properties and the corresponding particle-gas disturbance velocity ratio curves are given out through numerical computation. Further, several important conclusions on effect of particle property on growth and propagation of disturbance of interface of two-phase jet and particle disturbance property me presented on the basis of analyses of the obtained stability curves and particle-gas disturbance velocity ratio curves. These important conclusions can play a guiding role in studying development of two-phase jet and executing artificial controls over it in project practice.

关键词： stability of interface suspended solid particles particle disturbance property phase-coupled model jet shear layer

Non-spherical multi-oscillations of a bubble in a compressible liquid

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Journal of Hydrodynamics 2014年第6期26卷 848-855页

作者： WANG Qian-xi YANG Yuan-xiang tan Danielle SU Jian tan soon keat School of Mathematics University of Birmingham Maritime Research Centre School of Civil and Environmental Engineering Nanyang Technological University Sweimann Department of Mechanical Engineering National University of Singapore Nuclear Engineering Program COPPE Universidade Federal do Rio de Janeiro Nanyang Environment and Water Research Institute Nanyang Technological University

Bubble dynamics are associated with wide and important applications in cavitation erosion in many industrial systems, medical ultrasonics and underwater explosions. Two recent developments to this classical problem are reviewed in this paper. Firstly, computational studies on the problem have commonly been based on an incompressible fluid model. However, a bubble usually undergoes significantly damped oscillation due to the compressible effects. We model this phenomenon using weakly compressible theory and a modified boundary integral method. This model considers the energy loss due to shock waves emitted at minimum bubble volumes. Secondly, the computational studies so far have largely been concerned with the first-cycle of oscillation. However, a bubble usually oscillates for a few cycles before it breaks into much smaller ones. We model both the first- and second-cycles of oscillationand predict damped oscillations. Our computations correlate well with the experimental data.

关键词： compressible bubble dynamics weakly compressible theory boundary integral method

Flow Behavior Behind A Freely Suspended Cylinder in the Wake of A Stationary Cylinder

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China Ocean Engineering 2020年第5期34卷 708-717页

作者： GAO Yang-yang CHEN Wei-yi tan soon keat ZHANG Bao-feng Ocean College Zhejiang UniversityZhoushan 316021China Maritime Research Centre School of Civil Environmental EngineeringNanyang Technological University639798Singapore Powerchina Huadong Engineering Corporation Limited Hangzhou 311122China

The experiment of flow past a freely suspended circular cylinder in the wake of an upstream stationary cylinder was carried out in a re-circulating water channel using the Particle Image Velocimetry(PIV) technique. The upstream cylinder was fixed, while the downstream cylinder was suspended from a platform and allowed to move freely in the horizontal plane. The centre-to-centre spacing ratio between two tandem cylinders was initially kept at a constant value of 3.0. The instantaneous flow field and the orbital trajectories were analyzed to reveal the effect of the presence of the upstream cylinder and flow velocity on the dynamic response of the downstream suspended *** results showed that the upstream stationary cylinder has significant effect on modifying the flow patterns behind two tandem cylinders. Different trajectories of the downstream suspended cylinder with variation of flow velocity U were observed, such as:(1) depicting a figure-8 type motion at U = 0.27 m/s;(2) undergoing intermittent oscillations as it travels downstream at 0.3 m/s ≤ U ≤ 0.37 m/s;(3) successive moving downstream, no obvious streamwise oscillation observed at U = 0.43 m/s.

关键词： downstream suspended cylinder PIV camera orbital response flow pattern

Experimental Study on the Flow Around Two tandem Cylinders with Unequal Diameters

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Journal of Ocean University of China 2014年第5期13卷 761-770页

作者： GAO Yangyang ETIENNE Stephane WANG Xikun tan soon keat Ocean College Zhejiang University State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of Oceanography SOA Mechanical Engineering Department Ecole Polytechnique de Montreal Maritime Research Centre and School of Civil and Environmental Engineering Nanyang Technological University

In this paper, flow around two circular cylinders in tandem arrangement with unequal diameters has been investigated using the particle image velocimetry technique(PIV) in a water channel. The upstream to downstream diameter ratio was kept constant at d/D = 2/3, the centre-to-centre distance was varied from 1.2D to 5D and the Reynolds number was varied from 1200 to 4800. The flow characteristics were analyzed through ensemble-averaged patterns of velocity, vorticity, normalized Reynolds stress contours and streamlines. Based on ensemble-averaged and instantaneous flow fields, different flow patterns, including single-wakeshedding at small spacing ratio, bi-stable flow behavior(alternating behavior of reattachment and vortex shedding) at intermediate spacing ratio and co-shedding pattern at large spacing ratio were observed. The effects of Reynolds number and the centre-to-centre spacing ratio on flow patterns and turbulent characteristics were also investigated. It was found that the diameter ratio appears to have a certain effect on the flow patterns at intermediate spacing ratios, where the reattachment of shear layer depends on the lateral width of the wake flow in the lee of the upstream cylinder. Extensive discussion on the distributions of Reynolds stress and turbulent kinetic energy was presented.

关键词： tandem cylinders with unequal diameters PIV flow patterns Reynolds stress distribution

Numerical Study of an Oscillating Smaller Cylinder in the Wake of an Upstream Larger Cylinder

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Journal of Ocean University of China 2012年第2期11卷 111-117页

作者： GAO Yangyang YU Dingyong WANG Xikun tan soon keat Maritime Research Centre School of Civil and Environmental EngineeringNanyang Technological University639798Singapore College of Engineering Ocean University of ChinaQingdao 266100P.R.China Nanyang Environmental and Water Research Institute Nanyang Technological University639798Singapore

A numerical study of flow around two tandem cylinders with unequal diameters was carried out. The upstream larger cylinder was fixed and the downstream smaller cylinder was allowed to oscillate in the transverse direction only. Comparisons of the experimental and numerical results were made to investigate the effects of the gap ratio on the maximum vibration amplitude and vortex shedding frequency. The results showed that the vibration response of the smaller cylinder was significantly affected by the presence of the upstream larger cylinder, and resulted in greatly reduced vibration amplitudes. With an increasing gap ratio, the vibration amplitude increased. However, the magnitude was lower than that corresponding to a single cylinder (with the same diameter as that of the downstream smaller cylinder) under the same flow conditions.

关键词： tandem cylinders with unequal diameters numerical simulation gap ratio vibration amplitude

Experimental Study on Flow past A Rotationally Oscillating Cylinder

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China Ocean Engineering 2017年第4期31卷 495-503页

作者： GAO Yang-yang YIN Chang-shan YANG Kang ZHAO Xi-zeng tan soon keat Ocean College Zhejiang University Nanyang Environment and Water Research Institute and School of Civil and Environmental Engineering Nanyang Technological University

A series of experiments was carried out to study the flow behaviour behind a rotationally oscillating cylinder at a low Reynolds number （Re=300） placed in a recirculation water channel. A stepper motor was used to rotate the cylinder clockwise- and- counterclockwise about its longitudinal axis at selected frequencies. The particle image velocimetry （PIV） technique was used to capture the flow field behind a rotationally oscillating cylinder. Instantaneous and time-averaged flow fields such as the vorticity contours, streamline topologies and velocity distributions were analyzed. The effects of four rotation angle and frequency ratios Fr （Fr=fn/fv, the ratio of the forcing frequency fn to the natural vortex shedding frequency fv） on the wake in the lee of a rotationally oscillating cylinder were also examined. The significant wake modification was observed when the cylinder undergoes clockwise-and-counterclockwise motion with amplitude of π, especially in the range of 0.6≤Fr≤1.0.

关键词： rotational oscillation cylinder PIV frequency ratio wake flow pattern time-averaged flow field

考虑平台—群桩—水流—土体相互作用的导管架式海洋平台振动特性研究（英文）

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船舶力学 2018年第3期22卷 365-373页

作者：韩晓双周波 tan soon-keat 南洋理工大学土木与环境学院海事研究中心新加坡639798 大连理工大学工业装备结构分析国家重点实验室运载工程与力学学部船舶工程学院辽宁大连116024

文章分别采用平台—群桩—水流—土体相互作用模型和考虑附加水质量的等效桩模型,对三维平台结构在地震作用下的响应结果进行了比较研究。研究表明,等效桩模型的动力响应结果要大于考虑平台—群桩—水流—土体相互作用模型。分别采用平... 详细信息

文章分别采用平台—群桩—水流—土体相互作用模型和考虑附加水质量的等效桩模型,对三维平台结构在地震作用下的响应结果进行了比较研究。研究表明,等效桩模型的动力响应结果要大于考虑平台—群桩—水流—土体相互作用模型。分别采用平台—群桩—水流—土体相互作用的三维分析模型和简化模型计算平台的固有频率,通过比较两种模型的计算结果,对简化模型进行了频率修正,提出修正系数关系曲线。这种方法节省计算时间,提高计算精度,可为海洋平台的振动特性计算提供参考。

关键词：动力响应振动特性导管架式海洋平台地震响应平台一群桩一水流一土体相互作用固有频率

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含悬浮固粒射流界面稳定性研究

应用数学和力学 2000年第7期21卷 669-674页

作者：周泽宣 tan soon keat 林建忠浙江大学力学系南洋理工大学新加坡637898

利用气固两相耦合模型 ,理论推导出含悬浮固粒射流的稳定性方程 ,通过数值计算得到了两相射流稳定性特征曲线、固气扰动速度比值幅值曲线及固气相位差曲线。

关键词：界面稳定性悬浮固粒两相射流固粒扰动特性