Hagen-Poiffille流的再检验：微通道中流体阻力的形状依赖性

Comparing Poiseuille with 1D Navier-Stokes Flow in Rigid and Distensible Tubes and Networks

A comparison is made between the Hagen-Poiseuille flow in rigid tubes and networks on one side and the time-independent one-dimensional Navier-Stokes flow in elastic tubes and networks on the other. Analytical relations, a Poiseuille network flow model and two finite element Navier-Stokes one-dimensional flow models have been developed and used in this investigation. The comparison highlights the differences between Poiseuille and one-dimensional Navier-Stokes flow models which may have been unjustifiably treated as equivalent in some studies.

关于利用流体元性质定义的转捩参数的一个注记

A note on transition parameters defined with properties of fluid element

本文比较并讨论了基于流体元性质定义的转捩参数，从理论基础、物理定义和表达式出发，明确其在三类典型壁面剪切流中的适用限制。

Theoretical conditions of pipe flow transition: new approach to the old problem

For Hagen-Poiseuille flow the mechanism of laminar-to-turbulent transition originated from the deceleration of disturbed streams on the pipe wall is analyzed. An expression for the critical Reynolds number and the disturbance in the form of ring obstacle is derived. The good qualitative agreement between the theoretical results and published experimental data is demonstrated

On Exact Solutions of the Navier-Stokes Equations for Uni-directional Flows

In the present note, we show that the uni-directional flows in a rectangular channel and in a circular pipe are exact spatio-temporal solutions of the Navier-Stokes equations over a short time interval. We assert that the classical plane Poiseuille-Couette flow and Hagen-Poiseuille flow are time-independent approximations of the exact solutions if an appropriate initial velocity distribution at starting location is specified. Conceptually, there do not exist absolute steady flows starting from unspecified initial data. The classic experimental measurements by Poiseuille can be explained in ter…

A Framework for Input-Output Analysis of Wall-Bounded Shear Flows

We propose a framework to understand input-output amplification properties of non- linear partial differential equation (PDE) models of wall-bounded shear flows, which are spatially invariant in one coordinate (e.g., streamwise-constant plane Couette flow). Our methodology is based on the notion of dissipation inequalities in control theory. In particular, we consider flows with body and other forcings, for which we study the input- to-output properties, including energy growth, worst-case disturbance amplification, and stability to persistent disturbances. The proposed method can be applied t…

On the separate treatment of mixing and spreading by the reactive-particle-tracking algorithm: An example of accurate upscaling of reactive Poiseuille flow

The Eulerian advection-dispersion-reaction equation (ADRE) suffers the well-known scale-effect of reduced apparent reaction rates between chemically dissimilar fluids at larger scales (or dimensional averaging). The dispersion tensor in the ADRE must equally and simultaneously account for both solute mixing and spreading. Recent reactive-particle-tracking (RPT) algorithms can, by separate mechanisms, simulate 1) smaller-scale mixing by inter-particle mass transfer, and 2) mass spreading by traditional random walks. To test the supposition that the RPT can accurately track these separate mechan…

泊肃叶流中迁移蒸发液滴的动力学特性

Dynamics of an evaporating drop migrating in a Poiseuille flow

本研究采用CLSVOF方法与有限差分框架下的嵌入边界相变模型，探究管内泊肃叶流中迁移蒸发液滴的传热传质特性，验证了模型可靠性，揭示了Sh、Nu的稳态特性及Sh与Re、Sc的线性关联规律。

内部驱动弱弹性球在一般二次流中的动力学

Dynamics of an internally actuated weakly elastic sphere in a general quadratic flow

研究内部驱动弹性粒子在无粘性极限下在一般二次流中的动力学，分析其在不同Poiseuille流中的运动特性及弹性效应的影响。

重新思考管道流动稳定性：来自无网格全局分析的洞见

Rethinking Pipe Flow Stability: Insights from a Meshless Global Analysis

针对传统线性稳定性分析难以证实Hagen-Poiseuille流动不稳定性、受管道中心1/r项奇异性困扰的问题，本研究采用无网格框架开展全局稳定性分析，发现了区别于局部分析的新模态，验证了该方法无需多次模拟即可捕捉局部不稳定性的效用。

软液压结中的弹性流体动力相互作用

Elastohydrodynamic interactions in soft hydraulic knots

研究软液压结中弹性膜变形导致的非线性流量—压降关系，通过微流控实验与润滑理论模型揭示构型相关的限流机制，并展示整流与衰减应用。

流体中向turbulence的转变与固体中塑性的类比

On analogy between transition to turbulence in fluids and plasticity in solids

本文的研究对象是简单剪切流（如Hagen-Poiffille管流）的不稳定性机制，这是流体力学[1，2]中一个长期存在的问题。探讨了与固体理想塑性唯象理论的可能类比。它允许纳维-斯托克斯方程的扩展，使简单剪切流不稳定。根据von Mises [4]，假设流体中存在最大允许剪切应力或“屈服应力”。在实际应力达到这个值之后，一个新的物理机制将被激活，试图减少它们。这种机制导致了一种类似压力的力，必须将其加入到纳维-斯托克斯方程中。屈服应力本身是一个材料常数，它不依赖于特定流动的雷诺数。它将显示如何估计其值从实验数据。为了说明考虑附加力后流动特性的变化，本文给出了二维喷管内的非定常流动。动量源是通过Fluent提供的用户自定义函数接口引入到纳维-斯托克斯方程中的。初始数据和模拟结果总结在附录中。