Implicit large eddy simulation of passive scalar transfer in compressible planar jet
Implicit large eddy simulation of passive scalar transfer in compressible planar jet
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DOI：
10.1002/fld.4924
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发表时间：
2020-10
影响因子：
1.8
通讯作者：
Y. Tai;Tomoaki Watanabe;K. Nagata
中科院分区：
文献类型：
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作者：
Y. Tai;Tomoaki Watanabe;K. Nagata
采用隐式大涡模拟（ILES）方法研究了亚、超声速平板射流在可压缩湍流中的被动标量传递。本研究中使用的ILES依赖于用于空间和时间离散化的完全显式数值方案以及用作隐式亚网格尺度（SGS）模型的低通和激波捕获滤波器。ILES的结果进行了比较与直接数值模拟（DNS）数据库相同的流动。ILES的结果表现出良好的协议与DNS的速度和被动标量的一阶和二阶统计。湍流速度脉动的标量输运被ILES很好地捕获。射流的时间演化强烈地依赖于射流马赫数，其中较高的马赫数导致射流发展的延迟。速度场和被动标量场的马赫数依赖性在ILES和DNS之间是一致的。作为隐式SGS模型使用的低通滤波器有助于耗散湍流动能和标量方差。在目前的数值条件下，过滤器约占50%的耗散在一个充分发展的湍流射流。ILES中的耗散率是网格尺度耗散率和SGS耗散率之和，非常接近DNS中的耗散率，SGS耗散量由低通滤波器很好地控制。该滤波器还转储在高马赫数下由超音速射流外部的强压力波引起的速度场中的数值振荡。
Implicit large eddy simulation (ILES) of passive scalar transfer in compressible turbulence is evaluated for subsonic and supersonic turbulent planar jets. The ILES used in this study relies on fully explicit numerical schemes for spatial and temporal discretization and low‐pass and shock‐capturing filters used as an implicit subgrid‐scale (SGS) model. The ILES results are compared with the direct numerical simulation (DNS) database of the same flows. The ILES results exhibit good agreements with the DNS for first‐ and second‐order statistics of velocity and passive scalar. The scalar transport by turbulent velocity fluctuations is well captured by the ILES. The temporal evolution of the jet strongly depends on the jet Mach number, where a higher Mach number results in the delay of jet development. The Mach number dependence of velocity and passive scalar fields is consistent between the ILES and DNS. The low‐pass filters used as the implicit SGS model contribute to the dissipation of turbulent kinetic energy and scalar variance. Under the present numerical conditions, the filters account for about 50% of the dissipation in a fully developed turbulent jet. The dissipation rate in the ILES, which is the sum of the grid‐scale and SGS dissipation rates, is very close to the dissipation rate in the DNS, and the amount of the SGS dissipation is well controlled by the low‐pass filters. The filters also dump numerical oscillations in the velocity field caused by strong pressure waves outside the supersonic jet at the high Mach number.