Fractal characteristics of turbulent diffusion flames
Fractal characteristics of turbulent diffusion flames
复制标题
湍流扩散火焰的分形特征
DOI：
10.1080/00102209408935351
复制
发表时间：
1994
影响因子：
1.9
通讯作者：
F. Gao
中科院分区：
文献类型：
--
作者：
T. Miyauchi;M. Tanahashi;F. Gao
摘要对湍流扩散火焰进行了直接数值模拟，阐明了湍流扩散火焰的流动参数与分形维数、火焰锋面内截止等分形参数之间的关系。分形维数随雷诺数Re增大而增大，在雷诺数Re = 252时达到1.44。用箱计数法计算的内截止是基于熵的微尺度的2 ~ 3倍，非常接近最大熵耗散尺度。为了构造分形动态亚网格尺度模型，计算了火焰前缘标量梯度的概率密度函数。对过滤后的PDF的性能也进行了研究。过滤后的火焰前平均标量梯度出现一个截止点，约为火焰前内截止点的两倍。结果表明，用分形动态亚网格尺度模型对湍流扩散火焰进行大涡模拟是可行的。
Abstract Direct numerical simulations for turbulent diffusion flames were conducted to clarify the relationship between the flow parameters and the fractal parameters such as fractal dimension and inner cutoff of the flame front. The fractal dimension increases with Reynolds number Re, and reaches the value of 1.44 at Rex = 252. The inner cutoff, calculated by the box counting method, is two to three times that of the enstrophy based microscale and is very close to the scale of maximum enstrophy dissipation. To construct the fractal dynamic subgrid-scale model the probability density function of the scalar gradient on the flame front was calculated. The behavior of the filtered PDF was also investigated. Filtered mean scalar gradient on the flame front shows a cutoff, which is about two times that of the inner cutoff of the flame front. The results we have obtained show that large eddy simulations for turbulent diffusion flames by using the fractal dynamic subgrid-scale model may be possible.
DOI：
10.1063/1.857955
发表时间：
1991-07-01
期刊：
PHYSICS OF FLUIDS A-FLUID DYNAMICS
影响因子：
--
作者：
GERMANO, M;PIOMELLI, U;CABOT, WH
通讯作者：
CABOT, WH