作为二维流的基础的反复流动模式:从结构中预测统计数据
Jacob Page1, Peter Norgaard2, Michael P Brenner2,3
1School of Mathematics, University of Edinburgh, Edinburgh EH9 3FD, United Kingdom.
概括
研究人员使用不稳定的周期轨道重建了流统计数据. 这种动态系统方法克服了以前的局限性,为流体动力学提供了一个新的预测框架.
科学领域:
- 流体动力学 流体动力学
- 动态系统理论 动态系统理论
- 混沌理论是一个混乱理论.
背景情况:
- 流往往以高维状态空间中的轨迹为模型.
- 不稳定的简单不变量解决方案形成混乱的动态,但很难识别和权衡.
- 以前试图从这些解决方案中预测流量统计数据的尝试因缺乏已知的解决方案和权重理论而受到阻碍.
研究的目的:
- 开发一种在流中寻找不稳定的解决方案的方法.
- 使用这些解决方案,重建流的概率密度函数 (PDF).
- 建立基于动态系统的流统计的预测框架.
主要方法:
- 利用自动分化来发现不变的解决方案.
- 在解决方案精制中使用了轨迹依赖的损失函数.
- 将流轨迹转换为马尔科夫链,用于重量学习.
- 使用深度卷积自动编码器来识别最近的解决方案.
主要成果:
- 在二维科尔摩戈罗夫流中成功识别了数百个不稳定的周期轨道.
- 使用一组这些解决方案,证明了流重建的PDF文件.
- 建立了自我维持的动态过程和统计流特性之间的联系.
结论:
- 开发的方法在很大程度上解决了寻找和权衡不变的解决方案的局限性.
- 流统计,特别是PDF,可以使用不稳定的周期轨道准确地复制.
- 这种动态系统方法为了解和预测流提供了新的视角.
更多相关视频
11:00Experimental Investigation of Secondary Flow Structures Downstream of a Model Type IV Stent Failure in a 180° Curved Artery Test Section
Published on: July 19, 2016
11.6K
13:02Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow
Published on: February 27, 2016
12.2K
相关概念视频
Turbulent Flow
173
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent...
173
Introduction to Types of Flows
1.2K
Fluid flows are categorized by dimensionality and behavior, with one-dimensional flow being the simplest form, where properties like velocity and pressure change only along a single axis. Water moving through straight pipes exemplifies this flow type, as variations in other directions are minimal. One-dimensional analysis helps simplify understanding such flows, focusing solely on changes along the pipe's length.
Two-dimensional flow involves changes in both length and height, as seen in...
Two-dimensional flow involves changes in both length and height, as seen in...
1.2K
Laminar and Turbulent Flow
8.5K
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the...
8.5K
Plane Potential Flows
379
Plane potential flows simplify fluid motion by assuming the fluid to be irrotational and incompressible. These characteristics allow these flows to be described by a velocity potential function, ϕ, representing the flow speed in a given direction, and a stream function, ψ, that visualizes the flow path, both governed by Laplace's equation. These parameters help in estimating flow patterns, velocity distributions, and pressure fields around various hydraulic structures.
Uniform...
Uniform...
379
Poiseuille's Law and Reynolds Number
6.5K
Any fluid in a horizontal tube can flow due to pressure differences—fluid flows from high to low pressure. The flow rate (Q) is the ratio of pressure difference and resistance through a horizontal tube. The greater the pressure difference, the higher the flow rate. The flow resistance is expressed as:
6.5K
General Characteristics of Pipe Flow I
1.2K
Pipe flow refers to the movement of fluids within fully enclosed conduits, typically cylindrical in shape, such as water pipes or hydraulic hoses. These conduits are designed to withstand high-pressure gradients that drive fluid movement, contrasting with open-channel flows, where gravity is the primary driving force. Rectangular conduits, like air conditioning and heating ducts, generally operate at lower pressures and are less suited for high-pressure applications.
The classification of fluid...
The classification of fluid...
1.2K
