Experimental and Theoretical Study of Magnetohydrodynamic Ship Models

TL;DR

This paper combines theoretical modeling and experimental validation to study small-scale magnetohydrodynamic ships, providing a comprehensive framework and benchmarks for future research and design optimization.

Contribution

It offers a detailed theoretical and experimental analysis of small MHD ships, validating models without adjustable parameters and proposing an optimal design based on these results.

Findings

Successful theory-experiment agreement without adjustable parameters

Validation of Tafel and Kohlrausch laws in MHD ship context

Derivation of an optimal ship design from theoretical insights

Abstract

Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.