Establishment of the Direct Numerical Simulation Data Bases of Turbulent Transport Phenomena

为了建立紊流输运现象的直接数值模拟数据库，在过去的两年中，所有参与该项目的研究人员密切合作。各研究组的成果总结如下：Kasagi建立了各向同性湍流、湍流通道流和具有标量输运的湍流Couette-Poiseuille流数据库，并获得了湍流统计和准相干结构在湍流输运机制中的作用等重要信息。Nagano深入研究了各种光谱方法（Galerkin， tau和搭配）在湍流直接数值模拟中的准确性和相关的混叠误差。他建立了均匀湍流剪切流的统计数据库。Horiuti将Kleiser-Schumann （KS）方法应用于二维通道和方形管道的流动。在通道上，通过建立包括传热分析在内的数据库，验证了该方法与传统方法的一致性。本文将亥姆霍兹方程的切比雪夫多项式展开法与矩阵对角化法进行了比较。进一步研究了一种防止舍入误差累积的方法和将KS方法实现到超级计算中的算法。Miyauchi和Nagasaki进行了反应性/非反应性均匀各向同性湍流和反应性湍流混合层的直接数值模拟，假设温度和浓度为被动标量。建立了湍流能量、标量波动强度、能谱、标量波动输运方程预算、平均反应物和生成物浓度分布等数据库。Miyake为波浪通道和直矩形管道中的湍流以及湍流圆形射流开发了DNS代码，尽管最终没有完成。所有的代码都是基于有限差分方法。此外，还对这些流动进行了大涡模拟，以补充上述dns。少

All the investigators involved in this project worked in close cooperation during the past two years in order to establish the direct numerical simulation data bases of turbulent transport phenomena. The outcome of each research group is summarized as follows :Kasagi established the data bases of isotropic turbulence, turbulent channel flows and turbulent Couette-Poiseuille flows with scalar transport, and obtained important information on the turbulence statistics as well as the role of quasi-coherent structures in turbulent transport mechanism.Nagano intensively investigated accuracy of various spectral methods (Galerkin, tau and collocation) and associated aliasing errors in direct numerical simulations of turbulent flows. He established statistical data bases of homogeneous turbulent shear flows.Horiuti applied the Kleiser-Schumann (KS) method to two-dimensional channel and square-duct flows. In channel its consistency with conventional methods was validated with databases being ge … More nerated including heat transfer analysis. In duct, Chebyshev polynomial expansion solvers of Helmholtz equations were compared with the matrix-diagonalization technique. A method to prevent round-off error accumulation and algorithm to implement the KS method to supercomputing were further investigated.Miyauchi and Nagasaki conducted direct numerical simulations of reactive/nonreactive homogeneous isotropic turbulence and a reacting turbulent mixing layer with temperature and concentration assumed to be passive scalars. They made data bases of turbulent energy, scalar fluctuating intensity, energy spectra, budget of scalar fluctuation transport equation, mean reactant and product concentration profiles.Miyake developed DNS codes for turbulent flows in a wavy channel and a straight rectangular duct and for a turbulent round jet, though not finally completed. All the codes are based on finite-difference method. In addition, large eddy simulations of these flows were carried out to supplement the above DNSs. Less