Journal ArticleDOI
A general classification of three-dimensional flow fields
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TLDR
In this paper, the geometry of solution trajectories for three first-order coupled linear differential equations can be related and classified using three matrix invariants for elementary three-dimensional flow patterns defined by instantaneous streamlines for flow at and away from no slip boundaries for both compressible and incompressible flow.Abstract:
The geometry of solution trajectories for three first‐order coupled linear differential equations can be related and classified using three matrix invariants. This provides a generalized approach to the classification of elementary three‐dimensional flow patterns defined by instantaneous streamlines for flow at and away from no‐slip boundaries for both compressible and incompressible flow. Although the attention of this paper is on the velocity field and its associated deformation tensor, the results are valid for any smooth three‐dimensional vector field. For example, there may be situations where it is appropriate to work in terms of the vorticity field or pressure gradient field. In any case, it is expected that the results presented here will be of use in the interpretation of complex flow field data.read more
Citations
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Journal ArticleDOI
DNS-based predictive control of turbulence: an optimal benchmark for feedback algorithms
TL;DR: To achieve flow relaminarization in the predictive control approach, it is shown that it is necessary to optimize the controls over a sufficiently long prediction horizon T+ [gsim], which represents a further step towards the determination of optimally effective yet implementable control strategies for the mitigation or enhancement of the consequential effects of turbulence.
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Mechanisms for particle transfer and segregation in a turbulent boundary layer
TL;DR: In this paper, the authors examine the behavior of a dilute dispersion of heavy particles in a vertical channel flow, using pseudo-spectral direct numerical simulation to calculate the turbulent flow eld at a shear Reynolds number Re = 150, and Lagrangian tracking to describe the dynamics of particles.
Journal ArticleDOI
Vortex identification: New requirements and limitations
TL;DR: A survey of vortex-identification methods can be found in this paper, where the most widely used local criteria (applied point by point) sharing a basis in the velocity-gradient tensor ∇u are treated more thoroughly to recall their underlying ideas and physical aspects.
Journal ArticleDOI
Self-similar vortex clusters in the turbulent logarithmic region
TL;DR: In this article, the authors analyzed the organization of vortex clusters above the buffer layer of turbulent channels using direct numerical simulations at friction Reynolds numbers up to Re τ = 1900, where Re τ is the Reynolds number of vortex heads.
Proceedings ArticleDOI
Identification of swirling flow in 3-D vector fields
David Sujudi,Robert Haimes +1 more
TL;DR: An algorithm for identifying the center of swirling flow in 3-D discretized vector fields has been developed based on critical point theory and has been implemented as a visualization tool within pV3, a package for visualizing3-D transient data.
References
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Book
Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields
TL;DR: In this article, the authors introduce differential equations and dynamical systems, including hyperbolic sets, Sympolic Dynamics, and Strange Attractors, and global bifurcations.
A Reflection on Nonlinear Oscillations, Dynamical Systems, and Bifurcations of Vector Fields
J. Guckenheimer,P. J. Holmes +1 more
TL;DR: In this paper, the authors introduce differential equations and dynamical systems, including hyperbolic sets, Sympolic Dynamics, and Strange Attractors, and global bifurcations.
Book
Differential Equations, Dynamical Systems, and Linear Algebra
Morris W. Hirsch,Steve Smale +1 more
TL;DR: In this article, the structure theory of linear operators on finite-dimensional vector spaces has been studied and a self-contained treatment of that subject is given, along with a discussion of the relations between dynamical systems and certain fields outside pure mathematics.
Journal ArticleDOI
Direct simulation of a turbulent boundary layer up to R sub theta = 1410
TL;DR: In this paper, the turbulent boundary layer on a flat plate, with zero pressure gradient, is simulated numerically at four stations between R sub theta = 225 and R sub tta = 1410.