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
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