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Engineering Commons

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Mechanical Engineering

Portland State University

2017

Decomposition (Mathematics)

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Full-Text Articles in Engineering

Turbulent Boundary Layer Features Via Lagrangian Coherent Structures, Proper Orthogonal Decomposition And Dynamic Mode Decomposition, Naseem Ali, Murat Tutkun, Raul Bayoan Cal Apr 2017

Turbulent Boundary Layer Features Via Lagrangian Coherent Structures, Proper Orthogonal Decomposition And Dynamic Mode Decomposition, Naseem Ali, Murat Tutkun, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

High-speed stereo PIV-measurements have been performed in a turbulent boundary layer at Reθ of 9800 in order to elucidate the coherent structures. Snapshot proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are used to visualize the flow structure depending on the turbulent kinetic energy and frequency content. The first six POD and DMD modes show the largest and the lowest amount of energy and frequency, respectively. Lagrangian coherent structure (LCS) based on the algorithm developed using the variational theory is also applied to track the flow via attracting and repelling trajectories. The shapes and the length of the trajectories …