Observation and quantification of inertial effects on the drift of floating objects at the ocean surface

TL;DR

This study experimentally investigates how inertia affects the drift of floating objects on the ocean surface, using satellite-tracked drifters and Maxey--Riley theory to explain their trajectories.

Contribution

It demonstrates the role of buoyancy-induced inertia in floating object drift and applies a recent theoretical framework to interpret experimental observations.

Findings

Inertial effects significantly influence drift trajectories.

The Maxey--Riley theory explains observed inertial behaviors.

A closure method links theory parameters to physical properties.

Abstract

We present results from an experiment designed to better understand the mechanism by which ocean currents and winds control flotsam drift. The experiment consisted in deploying in the Florida Current and subsequently satellite tracking specially designed drifting buoys of varied sizes, buoyancies, and shapes. We explain the differences in the trajectories described by the special drifters as a result of their inertia, primarily buoyancy, which constrains the ability of the drifters to adapt their velocities to instantaneous changes in the ocean current and wind that define the carrying flow field. Our explanation of the observed behavior follows from the application of a recently proposed Maxey--Riley theory for the motion of finite-size particles floating at the surface ocean. The nature of the carrying flow and the domain of validity of the theory are clarified, and a closure proposal is made to fully determine its parameters in terms of the carrying fluid system properties and inertial particle characteristics.