Nonlinear state-space modelling of the kinematics of an oscillating circular cylinder in a fluid flow
Autor: | T. De Troyer, Mark Runacres, Koen Tiels, Joannes Schoukens, Jan Rik Decuyper |
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Přispěvatelé: | Faculty of Engineering, Engineering Technology, Acoustics & Vibration Research Group, Industrial Sciences and Technology, Electricity, Thermodynamics and Fluid Mechanics Group |
Rok vydání: | 2018 |
Předmět: |
Engineering
Aerospace Engineering FOS: Physical sciences Systems and Control (eess.SY) Computational fluid dynamics 01 natural sciences 010305 fluids & plasmas Physics::Fluid Dynamics Control theory 0103 physical sciences Fluid dynamics FOS: Electrical engineering electronic engineering information engineering Cylinder 0101 mathematics System identification Civil and Structural Engineering Van der Pol oscillator Nonlinear system identification Mathematical model business.industry Oscillation Mechanical Engineering Fluid Dynamics (physics.flu-dyn) Physics - Fluid Dynamics Mechanics Vortex-induced vibrations Polynomial nonlinear state-space model Computer Science Applications 010101 applied mathematics Forced cylinder oscillations Nonlinear system Control and Systems Engineering Nonlinear black-box modelling Signal Processing Computer Science - Systems and Control business |
Zdroj: | Vrije Universiteit Brussel |
DOI: | 10.48550/arxiv.1804.08383 |
Popis: | The flow-induced vibration of bluff bodies is an important problem of many marine, civil, or mechanical engineers. In the design phase of such structures, it is vital to obtain good predictions of the fluid forces acting on the structure. Current methods rely on computational fluid dynamic simulations (CFD), with a too high computational cost to be effectively used in the design phase or for control applications. Alternative methods use heuristic mathematical models of the fluid forces, but these lack the accuracy (they often assume the system to be linear) or flexibility to be useful over a wide operating range. In this work we show that it is possible to build an accurate, flexible and low-computational-cost mathematical model using nonlinear system identification techniques. This model is data driven: it is trained over a user-defined region of interest using data obtained from experiments or simulations, or both. Here we use a Van der Pol oscillator as well as CFD simulations of an oscillating circular cylinder to generate the training data. Then a discrete-time polynomial nonlinear state-space model is fit to the data. This model relates the oscillation of the cylinder to the force that the fluid exerts on the cylinder. The model is finally validated over a wide range of oscillation frequencies and amplitudes, both inside and outside the so-called lock-in region. We show that forces simulated by the model are in good agreement with the data obtained from CFD. |
Databáze: | OpenAIRE |
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