Study of axis-switching and stability of laminar rectangular jets using lattice Boltzmann method
- 作者：Huidan Yu ; Sharath S. Girimaji
- 关键词：Lattice Boltzmann equation ; Rectangular jet ; Transition ; Instability ; Axis switching
- 刊名：Computers and Mathematics with Applications
- 出版年：2008
- 期刊代码：37_08981221
- 类别：cp
- 出版时间：April 2008
- 卷：55
- 期：7
- 页码：1611-1619
- 文件大小：1572 K
摘要
We study stability characteristics and axis-switching behavior in low aspect-ratio (AR) laminar rectangular jets using lattice Boltzmann method. The objective of the study is to establish how the jet behavior changes with aspect ratio. Computations are performed with the D3Q19 multiple-relaxation-time lattice Boltzmann equation model. Simulations of three rectangular jets with 
, 1.5 and 2 at four Reynolds numbers, 10, 100, 150, and 200, are performed. The main conclusions of this study are: (1) At low Reynolds numbers (
), the three jets are stable and no axis switching is observed. (2) At intermediate Reynolds numbers (
), axis switching is clearly evident. The square jet (
) exhibits 45
axis switching and tends to become unstable. The two rectangular jets continue to be stable and exhibit 90 axis switching. (3) At high Reynolds numbers (
), all three jets are unstable and the irregular instantaneous cross-section still shows evidence of axis switching. Instability originates near the jet orifice and then propagates down the stream. The physics underlying the 45 and 90 axis switching are examined.
axis switching and tends to become unstable. The two rectangular jets continue to be stable and exhibit 90 axis switching. (3) At high Reynolds numbers ( and 90 axis switching are examined.