低速非对称射流边棱系统剪切流动的仿真分析-流体力学专业毕业论文.docx

Numerical study of low speed shear flow in Asymmetric Jet—edge System Abstract
Instability of shear flow iS one of the main research topics of a typical acoustic source model of shear flow,the self-sustained oscillation of system has been widely discussed.
The jet-edge system is generally described as an out from the nozzle directly rush to the wedge-shaped object with symmetrical this paper,flow behaviors of some asymmetric geometrical shaped systems which are controlled by the paralleled or angle shift between the midline of nozzle and object are discussed based on numerical simulations results.
It is found pared with symmetrical system,the asymmetric system’S frequencies
of oscillation are almost without any difference when the offset iS lower than 20%.but the
attenuation of oscillation’S amplitude increased quickly with the continued offset as well as a decline of the frequency especially when the offset is hig“r than 30%.And the value of oscillation’S amplitude shows some periodical attribute up and down with linear increase of
the angle between the midline of nozzle and object.
This paper insists that all the change of characteristic during the oscillation of shear flow which caused due to the asymmetric configuration should be paid
more attention in actua】conditions.
Key Words:Shear Flow;Edge—tone;Asymmetric System;Acoustic Source;Oscillation
万方数据
大连理工大学硕士学位论文
目 录
摘 要 。I
Abstract . .II
1 绪{念 1
1
3
5
7
9
2数值计算方法 10
_ : ..10
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..1l
..12
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Fluent中对控制方程的描述 ..13
时间离散格式 ..14
。14
。1 5
本章小结 .16
3模型建立与验证 17
.17
模型与网格类型的选择 ..1 7
。18
.20
一20
一23
.26
.27
.32
4计算结果及分析 33