Time-accurate local time stepping method based on flux updating
Time-accurate local time stepping method based on flux updating
复制标题
基于通量更新的精确本地时间步进方法
DOI：
--
复制
发表时间：
1994
期刊：
影响因子：
--
通讯作者：
R. Camarero
中科院分区：
文献类型：
--
作者：
X. Zhang;J. Trépanier;M. Reggio;R. Camarero
速度分量U和V的实测剖面，湍流动能k，以及由平衡关系8 =(0.3&)//推导出的湍流能量耗散率£。混合长度/的值是根据平均速度梯度和剪切应力的定义从数据中计算出来的。边界条件为尾迹边缘处U等于实验中实测边缘速度Ue， k和e满足零梯度条件，Ue dk/dx = e, Ue d£/dx = Ce2e/&，其中Ce2为模型常数之一。进行计算的流的结构如图1所示。尾迹产生模型是一个柔性板，通过改变板的形状在板的上下两侧产生不同的压力梯度来控制初始尾迹的性质。尾缘试验流动的边界层厚度、摩擦系数Cy、动量厚度雷诺数Re§等特性如表1所示。实验的细节和结果由Nakayama和Kreplin给出。计算中的步长最初取尾缘动量厚度0的0.5 × 10~倍，每50步增加一倍，直到达到0.26步长。大约需要1000个积分步骤来覆盖从后缘开始的大约400个距离，这被认为是一个近尾迹区域。
measured profiles of velocity components U and V, the turbulent kinetic energy k, and the dissipation rate of the turbulent energy £, which is deduced from the equilibrium relation 8 = (0.3&)//. The values of the mixing length / are calculated from the data using its definition in terms of the mean-velocity gradient and the shear stress. The boundary conditions are that U at the wake edges is equal to the measured edge velocity Ue measured in the experiment, k and e satisfy the zero-gradient conditions, Ue dk/dx = e and Ue d£/dx = Ce2e/&, where Ce2 is one of the model constants. The configuration of the flow for which the calculation is made is depicted in Fig. 1. The wake-generating model is a flexible plate whose shape is varied to produce different pressure gradients on the upper and lower sides of the plate controlling the properties of the initial wake. The characteristics of the test flow at the trailing edge including the boundary layer thickness, the friction coefficient Cy, and the momentum thickness Reynolds number Re§ are shown in Table 1. The details of the experiments and the results are given in Nakayama and Kreplin. The step size in the calculation is initially taken about 0.5 x 10~ times the momentum thickness 0, at the trailing edge and is doubled at every 50th step until the step size of 0.26, is reached. About 1000 integration steps are needed to cover a distance of about 400, from the trailing edge, which is considered a near wake region.