k方程描述了湍流能量的传输与产生,而epsilon方程描述了湍流速度脉动的耗散。k表示湍流能量,epsilon表示湍流速度脉动的耗散率。 k方程的一般形式为: ∂(ρk)/∂t + ∂(ρuk)/∂x + ∂(ρvk)/∂y + ∂(ρwk)/∂z = Pk - εk + ∂/∂x[(μ+μt)/σk ∂(ρk)/∂x] + ...
本人使用k-epsilon模型配合标准壁面函数法对明渠紊流进行计算,根据以往的经验,流速分布算得准不准和边界层内网格的关系密切,通常认为首层网格处于边界层对数区,即首层网格y+在30~70(也有人)之间,由于摩阻流速需要计算后确定,先按照网上一些y+计算器给出首层网格尺度,如http://www.pointwise.com/yplus/,其理论...
COMSOL Multiphysics 提供了多个不同的湍流问题求解公式:L-VEL、yPlus、Spalart-Allmaras、k-epsilon、k-omega、低雷诺数 k-epsilon,以及 SST 模型。所有这些公式都可以在 CFD 模块中调用,k-epsilon 和低雷诺数 k-epsilon 则在传热模块中可用。本博客简要介绍了我们为何要使用这些不同的湍流模型,如何从中选择,以及...
$y=\sin(\omega x)$平移到$y=\sin (\omega x+\varphi)$动态过程(交互式) 2019-12-03 18:42 − ###可以拖动滑动条的$\omega$和$\varphi$看动态效果 ... 狮山数学 0 342 The Epsilon-Greedy /UCB ("upper confidence bound") for MAB (Multiarmed-bandit) problem sometime in reinforcement...
The grid has to be refined such that y+ < 3. For the inflow boundaries, the following freestream values are recommended (7.75)ω∞=C1‖υ→∞‖2L, (μT)∞=(μL)∞10−C2, K∞=(μT)∞ρ∞ω∞, where L denotes the length of the ...
All low-Re k-epsilon models are designed for y+ near 1.2. v2f is an excellent turbulence model, good for vortical flows also, but it needs y+=1 meshes. I also needs separate licensing, which could be a problem...3. Practically all engineering flows are 3D, turbulence itself is a ...
摘要：文章利用StarCCM +软件建立模拟纯体燃烧器的典型实验糢型，通过在K-epsi Ion 湍流模型中模拟预混燃烧，比较了不同 模型对模拟结果的影响。为了验证糢拟的可靠性，文章将软件的仿真结果与其他研究团队真实测量的实验数据进行比对，进 而优化建立的仿真模型。关键词:StarCCM +: K-epsilon 湍流模型；预混燃烧...
Originally Posted by yhaomin2007 I think you can change the relaxation factor for k and epsilon equation Hi Haomin how should we change the under-relaxation-factors to have a more stable and also accurate result? e.g p=0.3, and the other ones(U, nuTilda,omega,k) 0.7, now, we should...
And how can i reduce the yplus value to one. And why is it a good result when it is one? For Standard Wall Functions , a valua bigger than thirty is good, right? Where comes the "good values"? And what do you mean with omgea based, SST models. I dont find them at wall functi...
value uniform 0; } epsilon: walls { type fixedValue; value uniform 0; } Thanks. Dear RLFerreira, Did you get any answer on that? I am trying the same settings to avoid walls functions with Y+ < 1 but the simulation explode... Thanks...