Estimating a sparse nonlinear dynamical model of the flow around an oscillating cylinder in a fluid flow using SINDy

The Sparse Identification of Nonlinear Dynamics (SINDy) toolbox can be used to estimate a nonlinear model of dynamical systems. SINDy is a dictionary method that applies sparse regression to a library of candidate functions. The effectiveness of SINDy has been demonstrated in a variety of fields. One such application is the modelling of the wake of a submerged cylinder in a flow. This is regarded as a canonical system for fluid-structure interactions. The SINDy method was found to be successful in modelling the flow around a stationary cylinder. In this work, the technique is applied to the wake of a submerged cylinder undergoing an imposed periodic oscillation. The experiment therefore strongly relates to the case of vortex-induced vibrations (VIV). VIV is challenging to model given that it exhibits much richer nonlinear dynamics than the stationary case. The study is carried out on the vorticity field in the wake of the cylinder. This work demonstrates that SINDy is capable of capturing the observed nonlinear dynamics.