Drift Due to Two Obstacles in Different Arrangements

TL;DR

This paper investigates how the arrangement of two cylinders affects fluid particle drift in an ideal, steady, two-dimensional flow, using numerical methods to analyze different configurations and their hydrodynamic interactions.

Contribution

It introduces a detailed numerical study of particle drift caused by two cylinders in various arrangements, providing new insights into hydrodynamic interactions and model accuracy.

Findings

Certain configurations increase particle drift compared to isolated cylinders.

Configurations with closer cylinders tend to decrease drift.

Results inform models of biogenic transport in fluid flows.

Abstract

We study the drift induced by the passage of two cylinders through an unbounded extent of inviscid incompressible fluid under the assumption that the flow is two-dimensional and steady in the moving frame of reference. The goal is to assess how the resulting total particle drift depends on the parameters of the geometric configuration, namely, the distance between the cylinders and their angle with respect to the direction of translation. This problem is studied by numerically computing, for different cylinder configurations, the trajectories of particles starting at various initial locations. The velocity field used in these computations is expressed in closed form using methods of the complex function theory and the accuracy of calculations is carefully verified. We identify cylinder configurations which result in increased and decreased drift with respect to the reference case when the two cylinders are separated by an infinite distance. Particle trajectories shed additional light on the hydrodynamic interactions between the cylinders in configurations resulting in different drift values. This ensemble of results provides insights about the accuracy of models used to study biogenic transport.