Effects of Thom disk on alleviating ground effects of a wall-mounted rotating cylinder

TL;DR

This paper examines how Thom disks can reduce ground effects caused by wall-mounted rotating cylinders, improving flow uniformity and propulsion efficiency through detailed numerical simulations.

Contribution

It introduces the use of secondary Thom disks near the ground to mitigate ground effects and optimize lift-to-drag ratio in Flettner rotors.

Findings

Secondary Thom disks significantly reduce ground-induced flow patterns.

Optimal placement of Thom disks maximizes lift-to-drag ratio.

Flow uniformity along the rotor surface is improved.

Abstract

This study investigates the effects of Thom disks on alleviating ground effects by wall-mounted rotating cylinders, also known as Flettner rotors, which utilize wind energy for ship propulsion. Through three-dimensional direct numerical simulations, our findings reveal that introducing a secondary Thom disk near the ground significantly reduces the three-dimensional flow pattern induced by the ground, leading to a more uniform pressure distribution along the rotor's surface. We also explore how the vertical placement of a secondary Thom disk influences wake dynamics and aerodynamic forces. Optimal placement of the secondary disk is found at the ground, which maximizes the lift-to-drag ratio.