非等直径并列四圆柱绕流特性数值研究

发布时间：2023-10-02 01:20

　　实际工程应用中许多现象都与钝体绕流息息相关,例如电厂的化学反应塔、桥墩、近海石油勘探平台、人在游泳时的手指等。我们都知道单元柱和两圆柱绕流作为钝体绕流的典型案例已经被较全面的研究过了,而多圆柱的绕流相关研究还不完善。因此本研究着重研究直径比D/d(D是中间两圆柱的直径,d是外侧两圆柱的直径)和间隙比g^*(=g/D_m,g 是圆柱和圆柱之间的垂直间隙,D_m=(D+d)/2是特征长度)的不同对于四圆柱绕流流场中的流动结构、涡脱频率以及圆柱上受力的影响。在目前的数值研究中,通过测量作用在每个圆柱、四圆柱系统上的作用力((?))和涡脱频率(f),研究分析了 D/d=0.4-1.6和g^*=0.25-5对四圆柱系统周围流场的影响。本次数值研究的雷诺数为100。随着D/d和g^*的变化,整个流场的流动结构可以被划分为:单钝体流动,混杂流动,近似周期流动,周期流动以及连锁流动。完整的直径比-间隙比(D/d-g^*)图可以被总结出来。最后观察分析作用在各圆柱和四圆柱系统上的力((...

【文章页数】：63 页

【学位级别】：硕士

【文章目录】：
摘要
Abstract
Acknowledgements
Nomenclature
Chapter1 Introduction
    1.1 Backgrounds
    1.2 Objectives
    1.3 Thesis outline
Chapter2 Domestic and international reasearch status
    2.1 Research status of flow around multiple cylinders
        2.1.1 Flow around two cylinders in a side-by-side arrangement
        2.1.2 Flow around two cylinders of different diameters
        2.1.3 Flow around multiple cylinders in various arrangement
    2.2 Summary
Chapter3 Computation details and validation
    3.1 Governing equations
    3.2 Computational domain
    3.3 Mesh resolution and validation
    3.4 Summary
Chapter4 Results and discussion
    4.1 Classification of flow patterns
        4.1.1 Single-bluff body flow
        4.1.2 Chaotic flow
        4.1.3 Quasi-periodic flow
        4.1.4 Periodic flow
        4.1.5 Interlocked flow
    4.2 Strouhal number
        4.2.1 Power spectral density of the fluctuating lift force
        4.2.2 Vortex shedding frequency
    4.3 Force coefficients
        4.3.1 Time-averaged drag coefficients and lift coefficients on cylinder1 and cylinder 2
        4.3.2 Root-mean-square drag coefficients and lift coefficients on cylinder1 and cylinder 2
        4.3.3 Total mean drag coefficients on the four-cylinder system
        4.3.4 Total root-mean-square drag and lift coefficients on the four-cylinder system
    4.4 The largest and smallest drag coefficients
    4.5 Summary
Conclusions
References
非等直径并列四圆柱绕流特性数值研究摘要



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