Restricted Research - Award List, Note/Discussion Page
Fiscal Year: 2023
1559 The University of Texas at Arlington (143447)
Principal Investigator: Chaoqun Liu,cliu@uta.edu,(817) 272-5151
Total Amount of Contract, Award, or Gift (Annual before 2011): $ 243,229
Exceeds $250,000 (Is it flagged?): No
Start and End Dates: 1/1/23 - 12/31/24
Restricted Research: YES
Academic Discipline: Department of Mathematics
Department, Center, School, or Institute: none
Title of Contract, Award, or Gift: EAGER: Development and Application of Liutex and Third Generation of Vortex Definition and Identification
Name of Granting or Contracting Agency/Entity:
National Science Foundation (NSF)
CFDA Link: NSF
47.041
Program Title:
NSF EAGER
CFDA Linked: Engineering Grants
Note:
(SAM Category 1.1.1.) Despite significant advancements in computational and experimental turbulence research, many basic features of turbulent flows are still not well understood. Among them is the dynamics of vortices. Quantitative understanding of vortex is essential for turbulence research and many engineering applications. In 1858, Helmholtz first defined vortex as tubes composed of so-called vortex filaments, which are, in fact, infinitesimal vorticity tubes. Vorticity has a rigorous mathematical definition with no clear physical meaning. Conversely, vortex has a physical meaning but until recently had no mathematical definition. Science and engineering applications have shown that the correlation between vortex and vorticity is very weak, especially in the near-wall region. Also, existing vortex identification methods, which are based on eigenvalues of the velocity gradient tensor, are all scalars and therefore strongly depend on the arbitrary thresholds. Liutex is a new physical quantity that represents local fluid rotation, i.e., vortex, and is a mathematically rigorous tool for vortex characterization. The major idea of Liutex is to extract the rigid rotation part from the fluid motion to represent the vortex. Given the novelty of Liutex, it is inevitable that the vortex dynamics be re-examined to develop a unique and accurate vortex identification method that is independent of thresholds. The proposed EAGER research will address how Liutex can (i) provide a rigorous mathematical definition of vortex, (ii) develop a high-order thresholdfree vortex identification method and software (iii) show the uniqueness of vortex structure for flow transition and fully developed turbulent flow in boundary layer, (iv) find the mechanism of the hairpin vortex formation, (v) find the mechanism of turbulence generation, sustenance, and vortex structure in turbulence, (vi) obtain quantified vortex (Liutex) evolution, (vii) understand the energy transformation paths between large and small vortices, and (viii) develop new fluid kinematics by using Liutex and RS decomposition, (ix) start research on new governing equations for turbulent flow.
Discussion: No discussion notes