A numerical investigation on the effect of the inflow conditions on the self-similar region of a round jet
A numerical investigation on the effect of the inflow conditions on the self-similar region of a round jet
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DOI：
10.1063/1.869626
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发表时间：
1998-04-01
影响因子：
4.6
通讯作者：
Nieuwstadt, FTM
中科院分区：
文献类型：
--
作者：
Boersma, BJ;Brethouwer, G;Nieuwstadt, FTM
本文研究了低雷诺数下空间发展自由圆射流的直接数值模拟。对空间演变流动（例如射流）的模拟需要边界条件，这允许夹带到跨越计算域横向边界的湍流中。满足这一要求的边界条件是所谓的无牵引边界条件。在表明这些边界条件导致射流横向边界附近的速度的正确行为之后，我们将考虑雷诺数为2.4 × 10（3）的射流的DNS，并将结果与Hussein等人[J.Fluid Mech.258，31（1994）]和Panchapakesan和Lumley [J.Fluid Mech.246，31（1994）]获得的实验数据进行比较。197（1993）]。数值模拟的结果与实验数据吻合得很好。接下来，我们使用DNS调查的影响的形状的速度分布在喷孔上的自相似标度的远场速度和剪切应力分布。证据支持的建议乔治[进展湍流（施普林格，纽约，1989年）]的细节自相似性依赖于初始条件。这一事实意味着，可能不存在普遍有效的相似标度的自由射流。(C)1998年美国物理学会。
In this paper we consider the direct numerical simulation (DNS) of a spatially developing free round jet at low Reynolds numbers. Simulation of a spatially evolving flow such as the jet requires boundary conditions, which allow entrainment into the turbulent flow across the lateral boundaries of the computational domain. The boundary conditions which satisfy this requirement are so-called traction free boundary conditions. After showing that these boundary conditions lead to a correct behavior of the velocity near the lateral boundary of the jet, we will consider the DNS of the jet flow at a Reynolds number of 2.4 x 10(3) and compare the results with experimental data obtained by Hussein et al. [J. Fluid Mech. 258, 31 (1994)] and by Panchapakesan and Lumley [J. Fluid Mech. 246, 197 (1993)]. The results of our numerical simulations agree very well with the experimental data. Next we use the DNS to investigate the influence of the shape of the velocity profile at the jet orifice on the self-similarity scaling for the far-field velocity and shear stress profile. Evidence is presented in support of the suggestion by George [Advances in Turbulence (Springer, New York, 1989)] that the details of self-similarity depend on the initial conditions. This fact implies that there may exist no universally valid similarity scaling for the free jet. (C) 1998 American Institute of Physics.