The mixing length model of DENTON code was modified to make it fit the development of boundary layer and moderate scale separation, and also reduce the dependence on experience. 改进了DENTON程序所使用的混合长度模型,使之能够适应壁面发展以及有适度分离流动的情况,并减少对经验的依赖。
Numerical Solution for Vertical Profile of Velocity in Flow Through Emergent Rigid Vegetation Based on Mixing Length Model 基于掺长模型非淹没刚性植被水流流速垂向分布的数值解
This paper deals mainly with the analysis of mixing loss in sequential transferring of crude oil, and the approach of calculation of mixing length at the pipeline terminal. 主要分析原油顺序输送过程中的混油损失,提出计算管路终端混油长度的方法。
The cause is that our understanding of overshooting still rests on the picture of phenomenological mixing length throry. 究其原因是因为人们对贯穿对流的理解依然停留在唯象的混合长理论图象上。
By laboratory similarity simulation test, empirical formula. of mixing length is obtained. 通过实验室模拟实验,确定了湍流情况下混合长度的经验公式;
The simple mixing length model is adopted to close the Reynolds averaged Navier Stokes equations. 湍流模型采用简单的混合长度模型。为提高迭代收敛速度,从多重网格理论出发,结合改良型LU隐式和迎风格式,对Reynolds平均三维可压缩Navier-Stokes方程进行求解。
According to the turbulent kinetic energy equation, mechanism about production and development of atmospheric turbulence of boundary layer is analysed. From this, the extent of turbulent motion scale, and turbulent mixing length expression which has a clear physical meaning are derived. 并根据湍流动能方程分析了大气边界层湍流产生和发展的能量机制,以此为判据推导出了湍流运动的尺度范围和物理含意较为清楚的混合长表达式。
The simulations based on single equation and two equations turbulent models were compared. The results of the both models at proper mixing length were consistent in general. 数值模拟的结果表明,用适当选取混合长度的单方程模型与双方程模型计算的结果基本一致;
The mixing length turbulence model and particle track method are used in the calculations. Based on the experimental data taken from references, the penetration, distribution of the concentration and velocity of a helium jet and their variations with time were predicted. 计算中应用混合长度湍流模型和粒子示踪法,根据文献提供的基础数据,预测了非稳态氦气射流的贯穿度、浓度分布、速度分布及其随时间的变化等。
The paper also puts forward the quasi-polynomial about calculation of mixing length on which the calculation of Reynolds stress is based. Finally, the calculated values are in good agreement with the field data. 提出了计算掺长的拟合多项式,基于提出的拟合多项式对雷诺应力进行计算,计算值与实测资料吻合良好。
On the basis of Prandtl's mixing length, the function relationship between mixing length and water depth was researched, which searched a feasible way on calculation of Reynolds stress and studied the closed Reynolds equations in the natural river. 在普朗特掺长假定的基础上对掺长与水深的函数关系进行分析研究,目的是寻求雷诺应力计算的可行途径,并为天然河流雷诺方程的封闭探求方法。
Based on fluid dynamic principle, the tidal velocity profile in the near-bottom layer in estuary and coast is established by introducing Prandtl mixing length theory and Von Karman self-similar theory. 本文从流体动力学原理出发,利用Prandtl混合长度和VonKarman自相似理论,建立河口海岸近底层潮流速分布的对数线性模式。
Based on these calculations, the authors analyze the science-practical nature of the Prandtl Mixing Length hypothesis, the momentum-transport theory, the Karman Similarity theory and the Taylor Vorticity Transport theory. 对卡门常数和普朗特混合长度进行了理论计算,并据此分析和论证了普朗特混合长度假说与动量传递理论和卡门关于紊流局部运动相似理论以及泰勒的涡旋传递理论的科学性和实用性。
In many engineering fields, it is not very well to solve the problems on the complex turbulent jet with Prandtl's turbulent mixing length model. 在许多工程问题中,利用Prandtl混合长度模型计算复杂类型的湍流射流问题已经不能满足要求。
Vertical profiles of mean velocity were observed experimentally, vertical distributions of shear velocity and turbulence intensity were analyzed, and eddy viscosity and Prandtl mixing length were evaluated both theoretically and empirically. 实验观测了含植物河流中流速垂向分布,分析了剪切应力和紊动强度的垂向变化,并以经验和理论公式估计了涡动黏滞系数和普朗特混合长度的数值。
The multihole nozzle ejector has lower noise and higher entrainment performance than the reference ejector at the ratios of medium and short mixing length. 最佳引射性能的多孔喷管引射器与参考引射器相比,在具有中等和较短混合室长度比时,不仅噪声可显著降低且引射性能亦可得到提高。
The mixing length ratio of the optimal multihole nozzle ejector is much shorter than that of the reference one if their entrainment coefficients are the same. 多孔喷管引射器引射系数达到最大值时,混合室长度要比参考引射器对应该引射系数时的混合室长度小得多。
In accordance with the theory of thin shear layer an analytical model is introduced for a parallel-multiple jets. Based on Prandtl's mixing length hypothesis, the analytical solutions for the model are obtained. 本文在簿剪切层理论基础上,建立了平行射流组的理论模型,并依据Prandtl混合长度理论,求出了该模型的分析解。
Calculating and measuring the full bin capacity, time of each bin, mixing delay capacity, feed time difference, and mixing length, etc., are investigated in this paper. 本文计算并测定了FA022型多仓混棉机的各仓一次充满容量和一次充满时间、混和时延容量、时间差及混和长度等;
A theoretical study on the surface-layer mixing length model 近地层混合长模式的理论研究
It is proved that prandtl's mixing length theory is based on the molecular momentum transport mechanism. 在这些基础上叙述了动量、热量和质量传输的模型,证明Prandtl湍流混合长度理论是分子动量传输的模型。
New theory predicts a shallower convection envelope for a given super giant in comparison with the usual mixing length theory. 与传统的理论相比,对具相同质量、光度和有效温度的恒星,新理论预期一较浅的对流区,超声速对流也被有效地抑制了。
The zero-equation model of turbulence is used for the sake of simplicity for engineering application, i.e. the Reynolds shear-stress term may be eliminated by the concept of Prandtl's mixing length theory. 为了工程应用上的简便,湍流模式采用零方程,即湍流剪应力的补充方程采用Prandtl的混合长度理论。
A modified local mixing length theory 一种修正的局部混合长理论
The equations of the boundary layer containing microbubbles on the plate are established, then calculated employing a simple mixing length model and a finite difference method. 建立了含有微气泡的平板边界层方程,并采用一种简单的混合长度模型和有限差分方法对该方程进行了数值计算。
The authors review the original mixing length theory and give a set of modified mixing length formula. 作者对此提出了质疑,并提出了一种修正的混合长公式。
Turbulent flow field of the mineral slurry in a 180 ° curved pipe is analyzed using the steady, three dimensional, incompressible Navier Stokes equations. The mixing length turbulent model is adopted. 采用三维、定常、不可压缩、时均NS方程和混合长湍流模型,建立了弯曲圆管中矿浆流动的控制方程和模型。
So, the mixing length scale in the k-ω SST model is modified according to the characteristic of transition flow and a modified k-ω SST two-equation model taking account of intermittence function effect is put forward. 因此,本文从转捩流动的物理特征出发对湍流模式中的混合尺度作出了修正,提出了一种考虑间歇函数影响的k-ωSST两方程湍流模式。
In our nation, reserved mixing length is usually short because of space and load limitations in retrofit projects. So the optimization research on ammonia injection and mixing devices, especially developing ammonia injection and high-efficiency mixing devices, is of great significance. 由于国内许多SCR脱硝装置均为电厂后期改造项目,受空间载荷限制预留的混合距离较短,因此对SCR系统喷氨混合装置进行优化研究尤其是开发高效喷氨混合装置具有重要意义。
Using the experimental results by Lamb et al, the characteristics of turbulence intensity and mixing length in the water with the high concentrated sediment suspension were analyzed. 依据Lamb等高浓度含沙水体实验结果,着重对波浪作用下高浓度水体的紊动强度分布、掺混长度进行了分析。