Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 11 of 11 for “"Finite Time Lyapunov Exponent"”.
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Biodynamic Analysis of Human Torso Stability using Finite Time Lyapunov Exponents
… the world afflicting 80% of the population some time in their life. Low back injury can result from a loss of torso stability causing excessive strain in soft tissue. This investigation seeks to apply existing methods to new applications and to develop new methods to assess torso stability. …
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The rotor-oscillator flow : searching for coherence amidst chaos
… parcels surrounded by a sea of chaos. Through finite-time Lyapunov exponent (FTLE) analysis, a roughly optimal coupling was found. The parameters that describe this coupling are the nondimensional oscillation amplitude [epsilon] = 0.125 and frequency [lambda] = 0.4[pi]. In order to understand …
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Atmospheric Lagrangian transport structures and their applications to aerobiology
… fluid systems. We apply powerful notions such as finite-time Lyapunov exponent (FTLE) and the associated Lagrangian coherent structures (LCS) and we attempt to provide mathematical explanations and frameworks for some applied questions which are based on realistic concerns of atmospheric transport …
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A numerical study on microbubble mixer
… system, using Poincare sections and the Finite-time Lyapunov exponent. These indicators provide evidence that by properly blinking between different streaming patterns, chaotic-like mixing can be created inside our mixer. The observation made from numerical results that the size of the …
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Identifying dynamical boundaries and phase space transport using Lagrangian coherent structures
… which have qualitatively different fates. The finite-time Lyapunov exponent (FTLE) method is a general and equation-free method that identifies codimension-one sets which have a locally high rate of stretching around which maximal exponential expansion of line elements occurs. These …
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Experimental and Simulation Based Dynamic Assessment of Flexion and Extension Movements of Torso
… maximum voluntary exertion force. The maximum finite-time Lyapunov exponent, λ<sub>Max</sub>, was used to quantify the dynamic stability. Values of λ<sub>Max</sub> increased with fatigue, suggesting dynamic stability of the torso decreases with muscle fatigue. Fatigue-by-task asymmetry …
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Advancing the theory and applications of Lagrangian Coherent Structures methods for oceanic surface flows
… because it operates on multiple length- and time-scales that are set by the underlying dynamics. Building on the recent emergence of Lagrangian methods, this thesis investigates the present-day abilities to describe and understand the organization of flow transport at the ocean surface, …
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Vortex detection and tracking in massively separated and turbulent flows
… coherent structures (LCS) analyses including the finite-time Lyapunov exponent (FTLE), the geodesic LCS, and the Lagrangian-Averaged Vorticity Deviation (LAVD). Each of \h{these} Lagrangian methods \h{is} applied at the centers and boundaries of the vortices to detect the vortex dynamics. </p> …
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Lagrangian Visualization and Real-Time Identification of the Vortex Shedding Time in the Wake of a Circular Cylinder
… the locations of vortices and their shedding time could increase the effectiveness of the control techniques. In the current work, two-dimensional, two-component velocity data was collected in the wake of a circular cylinder using a planar digital particle image velocimetry (DPIV) measurement …
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Direct numerical simulation of an aerofoil at high angle of attack and its control
… been carried out using the Q-criterion and the Finite-Time Lyapunov Exponent technique. Based on the fundamental knowledge achieved in studying the static and the dynamic stall, we introduced a biomimetic passive control technique to mitigate the aerodynamic performance degradation typical of …
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Data-Driven Variational Multiscale Reduced Order Modeling of Turbulent Flows
… not only Lagrangian fields (e.g., the finite time Lyapunov exponent (FTLE)), but also Eulerian fields (e.g., the streamfunction). We emphasize that the new Lagrangian ROMs do not employ any closure modeling to model the effect of discarded modes (which is standard procedure for …