Interpretation and prediction of the three-dimensional coherent structure and its dynamics of tornado-like vortex via delayed proper orthogonal decomposition

Physics of Fluids, Journal Year: 2025, Volume and Issue: 37(1)

Published: Jan. 1, 2025

This study proposes a three-dimensional mode-based surrogate framework to predict the tornado-like vortex (TLV) derived from fuzzy neural network and delayed proper orthogonal decomposition method. First, near-break-down TLV is simulated via large-eddy simulation, its mean, fluctuating statistical flow feature analyzed. Then, spatiotemporal features of coherent structure are extracted interpreted. Next, capability proposed future state an unsteady chaotic field systematically evaluated, including variation velocity, pressure, vorticities as well statistics. Finally, parametric analysis also conducted investigate influence three key parameters [i.e., Fuzzy rules or output (K1 K2), time embedding number (d)] contained in step forward prediction (K) on predicted accuracy. Results show that for TLV, wandering effect largely affects dynamical feature, characteristics distinct, exhibiting essence swirling jet flow. 3D model can correctly with relative error less than 2% radial, tangential, vertical velocity component. It found time-delayed has great Thus, achieve optimal predicting effect, it suggested d taken 8, K1, K2 18, when making multi-step predictions, largest K should not exceed 7.

Language: Английский

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CFD- and BPNN- based investigation and prediction of air pollutant dispersion in urban environment

Sustainable Cities and Society, Journal Year: 2023, Volume and Issue: 100, P. 105029 - 105029

Published: Oct. 29, 2023

Language: Английский

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The linear-time-invariance notion of the Koopman analysis. Part 2. Dynamic Koopman modes, physics interpretations and phenomenological analysis of the prism wake

Journal of Fluid Mechanics, Journal Year: 2023, Volume and Issue: 959

Published: March 22, 2023

This serial work presents a Linear-Time-Invariance (LTI) notion to the Koopman analysis, finding consistent and physically meaningful modes addressing long-standing problem of fluid-structure interactions: deterministically relating fluid structure. Part 1 (Li et al., 2022) developed Koopman-LTI architecture applied it pedagogical prism wake. By systematic procedure, LTI generated sampling-independent linearization that captured all recurring dynamics, six corresponding, orthogonal, in-synch excitation-structure response mechanisms. 2 analyzes modal duplets' underpin their physical interpretations, providing phenomenological revelation subcritical dynamical mode shape, results show two mechanisms at St1=0.1242 St5=0.0497 describe shear layer associated B\'ernard-K\'arm\'an shedding, turbulence production, which together overwhelm upstream crosswind walls by instigating reattachment-type response. The on-wind walls' similarity renders them spectrally unified interface. Another four harmonic counterparts, namely subharmonic St7=0.0683, second St3=0.2422, ultra-harmonics St7 =0.1739 St13=0.1935, govern downstream wall. 2P wake is also observed as an embedded bluff-body Finally, this discovered vortex breathing phenomenon, describing constant energy exchange in wake's circulation-entrainment-deposition processes. With Koopman-LTI, one may pinpoint exact excitations responsible for specific structural response, or vice versa.

Language: Английский

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Best practice guidelines for the dynamic mode decomposition from a wind engineering perspective

Journal of Wind Engineering and Industrial Aerodynamics, Journal Year: 2023, Volume and Issue: 241, P. 105506 - 105506

Published: Aug. 24, 2023

Language: Английский

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Learning-based hierarchical cooperative eco-driving with traffic flow prediction for hybrid electric vehicles

Energy Conversion and Management, Journal Year: 2024, Volume and Issue: 321, P. 119000 - 119000

Published: Sept. 11, 2024

Language: Английский

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The role of transverse inclination on the flow phenomenology around cantilevered prisms and the tripole wake mode

Journal of Fluids and Structures, Journal Year: 2023, Volume and Issue: 118, P. 103837 - 103837

Published: Feb. 2, 2023

Language: Английский

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Isolation, decomposition, and mechanisms of the aerodynamic nonlinearity and flow field phenomenology of structure-motion-induced dynamics in fluid–structure interactions

Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(4)

Published: April 1, 2023

This study focuses on the aerodynamic nonlinearity and flow field phenomenology of structure-motion-induced dynamics in fluid–structure interactions (FSI), which is essential for response prediction. Through dynamic-meshing large-eddy simulations with near-wall resolution, nonlinear damping still wind has been isolated by forced vibration, its phenomenological characteristics physical mechanisms have analyzed. The results show that can account up to 30% total damping, cannot be ignored also reveals three-dimensional vorticity vary nonlinearly structure motion, leading hysteresis effect between forces displacement. Furthermore, in-depth analysis discloses eight types coherent substructures, including Stick, Phone, Bowknot, Crutch, Droplet, Bat, Horn, Flag are solely induced structural motion. Insights into these substructures' formation, evolvement, dissipation, superposable magnitude disclosed. research offers a new perspective understanding nature FSI, serving as reference various FSI applications, bridges, high-building design, other related fields.

Language: Английский

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Enhanced Koopman operator-based robust data-driven control for 3 degree of freedom autonomous underwater vehicles: A novel approach

Ocean Engineering, Journal Year: 2024, Volume and Issue: 307, P. 118227 - 118227

Published: May 23, 2024

Language: Английский

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Reconstruction and short-term prediction of wind pressure field on cylindrical coal sheds under undisturbed conditions using dynamic mode decomposition

Journal of Wind Engineering and Industrial Aerodynamics, Journal Year: 2025, Volume and Issue: 258, P. 106017 - 106017

Published: Jan. 30, 2025

Language: Английский

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Flow mechanism of a vibrating prism using the combined K-nearest neighbor and dynamic mode decomposition method

Journal of Wind Engineering and Industrial Aerodynamics, Journal Year: 2025, Volume and Issue: 258, P. 106013 - 106013

Published: Feb. 2, 2025

Language: Английский

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