Lateral forces on a magnet falling in a conducting pipe

Abstract

Purpose

The purpose of this paper is to investigate the lateral forces during the fall of a magnet in a conducting pipe, when the direction of magnetization of the magnet is fixed. If the direction of magnetization is not parallel to the axis of the pipe, lateral forces occur and a decentration of the magnet happens.

Design/methodology/approach

The problem is studied numerically, with a T − h 3D FE formulation well‐suited for the problem. Computational results are compared with experimental results.

Findings

The physical model is given and the main force coefficients analyzed. The lateral forces and the decentration phenomenon are studied as a function of the main parameters (thickness and radius of the pipe).

Originality/value

The direction of magnetization is a key parameter to analyze the dynamics of a magnet motion inside a conducting pipe, when the radii of the pipe and the magnet are not so close. This analysis with a fixed direction of magnetization allows one to quantify the lateral forces and the decentration, and is a first step to understand the complete motion which includes the rotation which can be linked to the decentration.

Citation

Dufour, S., Vinsard, G. and Brancher, J.‐. (2012), "Lateral forces on a magnet falling in a conducting pipe", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 31 No. 6, pp. 1625-1636. https://doi.org/10.1108/03321641211267038