Turbulent kinetic energy equation and free mixing
Turbulent kinetic energy equation and free mixing
复制标题
湍流动能方程与自由混合
DOI：
--
复制
发表时间：
1973
期刊：
影响因子：
--
通讯作者：
P. Bradshaw
中科院分区：
文献类型：
--
作者：
T. Morel;T. Torda;P. Bradshaw
对自由剪切流动进行了计算，以考察先前成功应用于壁面流动的几个概念的有效性。该方法属于微分方法。紊流是通过引入一个附加的偏微分方程，即紊流剪切应力的输运方程来考虑的。湍流的结构是根据Bradshaw等人建立的。该模型在边界层中得到了成功的应用，并证明了其对其他流动的适用性。报告的工作与早先尝试使用这种方法计算自由流动的工作有很大不同。最重要的区别是，中心线周围的区域是通过调用相互作用假设来处理的（关于由速度极值分隔的区域中的湍流结构）。研究了低、中马赫数条件下可压缩性对剪切层扩展的影响。在没有详细的自由流动实验的情况下，来自边界层的证据表明，在低马赫数下，湍流结构不受可压缩性的影响。本模型在一系列自我保护和发展的流动中进行了测试，包括使用相同的经验输入的压力梯度。建立了湍流结构与剪切层扩散速率的关系。
Calculation of free shear flows was carried out to investigate the usefulness of several concepts which were previously successfully applied to wall flows. The method belongs to the class of differential approaches. The turbulence is taken into account by the introduction of one additional partial differential equation, the transport equation for the turbulent shear stress. The structure of turbulence is modeled after Bradshaw et al. This model was used successfully in boundary layers and its applicability to other flows is demonstrated. The work reported differs substantially from that of an earlier attempt to use this approach for calculation of free flows. The most important difference is that the region around the center line is treated by invoking the interaction hypothesis (concerning the structure of turbulence in the regions separated by the velocity extrema). The compressibility effects on shear layer spreading at low and moderate Mach numbers were investigated. In the absence of detailed experiments in free flows, the evidence from boundary layers that at low Mach numbers the structure of turbulence is unaffected by the compressibility was relied on. The present model was tested over a range of self-preserving and developing flows including pressure gradients using identical empirical input. The dependence of the structure of turbulence on the spreading rate of the shear layer was established.