Liutex-third generation of vortex definition and identification methods

LIU Chaoqun

doi:10.7638/kqdlxxb-2020.0015

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Liutex-third generation of vortex definition and identification methods

更新时间：2026-05-28

- Liutex-third generation of vortex definition and identification methods
- Vol. 38, Issue 3, Pages: 413-431(2020)
- 作者机构：
  
  美国德州大学阿灵顿分校, 得克萨斯阿灵顿,美国,76019
- 作者简介：
- 基金信息：
- DOI：10.7638/kqdlxxb-2020.0015
  CLC： V211.1;O357.5
- Published：2020
- 稿件说明：
移动端阅览
刘超群. Liutex-涡定义和第三代涡识别方法[J]. 空气动力学学报, 2020, 38(3): 413-431.

LIU Chaoqun. Liutex-third generation of vortex definition and identification methods[J]. 2020, 38(3): 413-431.
刘超群. Liutex-涡定义和第三代涡识别方法[J]. 空气动力学学报, 2020, 38(3): 413-431. DOI： 10.7638/kqdlxxb-2020.0015.

LIU Chaoqun. Liutex-third generation of vortex definition and identification methods[J]. 2020, 38(3): 413-431. DOI： 10.7638/kqdlxxb-2020.0015.

摘要

本文回顾了涡定义和涡识别方法的发展历史，着重介绍了作者UTA（University of Texas at Arlington）团队及其合作者在涡科学和湍流研究的一些最新学术创新成果。UTA团队发现了可以定量描述流体刚性转动部分的物理量——Liutex向量，其主要思想是把流体刚性转动从流体运动中提取出来，进而用Liutex来定义和识别涡结构，并已在广泛应用中证明了其作为涡识别方法的优越性。基于Liutex向量可以进一步研究涡量分解、速度梯度张量分解、流体运动分解、湍流结构、湍流生成机理以及旋涡的科学识别，为流体运动学的发展开辟了广阔的研究空间。区别于第一代涡识别方法和第二代涡识别方法，Liutex是一个向量，其方向代表当地转轴，大小代表当地流体刚性旋转角速度的二倍。本文详细介绍了基于Liutex向量的第三代涡的定义和识别方法，包括Liutex等值面、Liutex-Omega等值面、Liutex向量线、Liutex涡核线、以及最新发现的中低雷诺数湍流边界层中的Liutex-5/3幂次相似律，其发现很大程度上扩大了传统湍流能谱幂次律的适用范围，对建立湍流模型具有重要意义。

Abstract

A short review of the history of vortex identification is made. The article mainly introduces the new academic breakthrough and newest vortex identification methods in vortex science and turbulence research

developed by the research team and their collaborators at University of Texas at Arlington (UTA) led by Prof. Chaoqun Liu. Vortex is very common in nature but has no strict definition. Almost all textbooks in the world recognize vortex as vorticity tube and there is no difference between vorticity tube and vortex. Confusing

vortex with vorticity may be one of major obstacles of vortex science and turbulence research. The most significant progress made by Liu and his team is finding a physical quantity called Liutex which is a vector and can be applied to describe the fluid rotation quantitatively first time in history

which has many advantages over other vortex identification methods. This has been proved by wide applications and accepted gradually by the vortex and turbulence community as a unique mathematical definition of vortex. This discovery opens the gate of quantified research on vortex and turbulence. The main idea is to extract the rigid rotation from fluid motion called Liutex as a new physical quantity which is then applied for vortex definition

vorticity decomposition

velocity gradient tensor decomposition

fluid motion decomposition

turbulence structure

mechanism of turbulence generation and vortex identification. This also means to revisit the whole fluid kinematics. Being different from first generation of vortex identification methods which uses vorticity to measure vortex

and from the second generation of vortex identification methods which uses vortex criteria like

、

and

for vortex identification (they are all scalars)

Liutex is a vector. The third generation of vortex visualization and identifiction methods like Liutex vector

Liutex lines

Liutex iso-surface

Liutex-Omega iso-surface

Liutex core center lines

and Liutex Similarity (-5/3 Power law) are all briefly introduced in this paper. Liutex Similarity law could be a very significant discovery which could be very important to turbulence modeling.

关键词

Keywords

references

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