Exit Dynamics of a Square Cylinder

TL;DR

This study experimentally examines the dynamics of a square cylinder crossing an air-water interface, analyzing interface deformation, forces involved, and flow patterns at various speeds.

Contribution

It provides new experimental insights into the forces and interface behavior during a cylinder's vertical crossing of a water-air interface.

Findings

Interface deformation varies with speed.

Drag and entrainment forces are quantified.

Flow visualization reveals flow patterns around the cylinder.

Abstract

In this paper, we experimentally investigate the exit dynamics of a square cylinder, that is initially fully immersed in a water tank and that crosses the interface perpendicularly to its symmetry axis. The cylinder moves upwards at a constant velocity in the vertical direction till the cylinder exits out of the water into the air. The experiments were performed at different traveling speeds. The images of the cylinder crossing the interface were taken using a high-speed camera. The images were used to track the interface deformation when the cylinder approaches and crosses the interface. On top of these measurements, the force required to move the cylinder was simultaneously measured in order to estimate the drag force during the travel in the tank, the force of entrainment, and the force of crossing over the interface. Particle image velocimetry was performed to visualize the flow. Correlations between the different measurements are inspected.