A Study on the Turbulent Mixing and Chemical Reaction by the Stochastic Differential Equation and Random Fourier Modes Method

随机微分方程和随机傅里叶模态方法研究湍流混合与化学反应

基本信息

批准号：
13650174
负责人：
SAKAI Yasuhiko
金额：
$ 2.3万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650174/
关键词：
Stochastic Process Model Fourier Modes Method Turbulence Mixing Chemical Reaction Molecular Mixing Model Rapid Distortion Theory Turbulent Pipe Flow 確立微分方程式

项目摘要

The progress and results of the research are summarized in the following,Object (A) <Simulations by the Stochastic Model>___-The axisimmetric plume from a point source in the fully developed turbulent pipe flow has been simulated by the probability density function method (pdf) method. The particle velocity was modeled by a stochastic differential equation (a generalized Langevin model expressed in the cylindrical coordinates), and the two kinds of molecular mixing model, i.e., the Dopazo's deterministic model and the modified Curl's model have been used. It is found that both models are useful to predict the radial profiles of the mean concentration and fluctuation r.m.s.concentration. Next, the reactive mixing layer with second-order chemical reaction in the grid-turbulence has been simulated by the pdf method. It is found that as the molecular mixing model the binomial Langevin model is suitable to predict the pdf of the reactive scalar quantities. Further, the new generalized Lange … More vin model for the axisymmetric turbulent jet has been developed, and the conserved scalar field has been simulated by the Dopazo's model. Consequently, the scalar moments up to the second-order could be predicted satisfactorily.Object (B) <Simulations by the Random Fourier Modes Method>___-At first, a new method to simulate the turbulent field around a two-dimensional circular cylinder has been developed by the combination of the random Fourier modes method, the rapid distortion theory and the wake vortex shedding model. Then, the distribution of the second-order moment and spectrum of the velocity field have been calculated and compared with the experimetal data. It is found that the simulation results show good agreements with the experimental data. Next, the reactive scalar mixing layer has been simulated by the combination of the randam Fourier modes method and two-particle backward diffusion technique or the molecular mixing model of the pdf method. The agreements between the simulation results and experimental data could be observed. Further, the simulation method of the turbulent flow around the various bluff bodied has been developed, and the statistics of the material line in the homogeneous isotropic turbulence has been investigated by the random Fourier modes method. Less

研究进展和结果总结如下：对象（A）<随机模型的模拟>___-采用概率密度函数法模拟了充分发展的湍流管流中来自点源的轴对称羽流（ pdf）方法通过随机微分方程（以柱坐标表示的广义朗之万模型）和两种分子混合模型来建模，即使用Dopazo 确定性模型和改进的Curl 模型发现，这两种模型都可用于预测网格中具有二阶化学反应的反应混合层的平均浓度和波动均方根浓度。用pdf方法模拟了湍流，发现二项式Langevin模型适合预测反应标量的pdf。建立了轴对称湍流射流的Lange … More vin模型，并通过Dopazo模型对守恒标量场进行了模拟，可以很好地预测二阶标量矩。对象(B)<模拟。随机傅里叶模态方法>___-首先提出了一种结合随机傅里叶模态来模拟二维圆柱体周围湍流场的新方法方法、快速畸变理论和尾流涡脱落模型计算了速度场的二阶矩和谱，并与实验数据进行了比较，发现模拟结果与实验数据吻合良好。接下来，结合随机傅里叶模态方法和二粒子后向扩散技术或pdf方法的分子混合模型对反应标量混合层进行了模拟，模拟结果与实验数据一致。更远，建立了各种钝体周围湍流的模拟方法，并用随机傅里叶模态法研究了均匀各向同性湍流中的物质线统计。