Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Numerical Study of Underwater Vehicle’s Magnetic Stealth Characteristic
Liang Dong, Jianwei Wu, Haixiong Zhu, Yun Wang*, Qingjie Meng, Weihua Shi
Wuhan Second Ship Design and Research Institute, Wuhan, Hubei, China*Corresponding author

extrapolation method in magnetic silencing of ships based on theTikhonov regularization method. Zhou (2010) researches on themagnetic field extrapolation of ships based on boundary equivalentmagnetic source method.

ABSTRACTIn this paper, the underwater vehicle’s magnetic stealth characteristic isnumerically studied based on the finite element method (FEM). The
inductive magnetic flux density of an underwater vehicle with different
sailing direction is simulated and analyzed. It shows that the maximum
inductive magnetic flux density is inversely proportional to the distanceabove the ship. Because of the influence of geomagnetic south andnorth poles, the maximum inductive magnetic flux density is larger
when the underwater vehicle sails south or north comparing to east or
west. It can be concluded that when the underwater vehicle is about tohide from the magnetic anomaly detection device on the aircraft, it issuggested that the underwater vehicle dives deeper and sails east or
west instead of other direction.

The related work mainly researches on the computing method of themagnetic characteristic. In this paper, the mathematical calculation
model of magnetostatic problem is firstly introduced. Then themagnetic stealth characteristic of an underwater vehicle with different
sailing direction and different depth is numerically simulated andanalyzed. Finally, some useful conclusions are made based on thesimulated results which is that when the underwater vehicle is about tohide from the magnetic anomaly detection device on the aircraft, it issuggested that the underwater vehicle dives deeper and sails east or
west instead of other direction.

KEY WORDS: Underwater vehicle; Magnetic stealth characteristic;
Inductive magnetic flux density.

MATHEMATICAL CALCULATION MODELINTRODUCTION

In a magnetostatic problem, the magnetic field is produced by DC
currents flowing in conductors/coils and by permanent magnets. The
electric field is restricted to the objects modeled as real (non-ideal)
conductors. The electric field existing inside the conductors as aconsequence of the DC current flow is totally decoupled from themagnetic field. Thus, as far as magnetic material properties areconcerned, the distribution of the magnetic field is influenced by thespatial distribution of the permeability. There are no time variation
effects included in a magnetostatic solution, and objects are considered
to be stationary. The energy transformation occurring in connection
with a magnetostatic solution is only due to the ohmic losses associatedwith the currents flowing in real conductors.

Normally underwater vehicles are made up of ferromagnetic materials
such as steel. As a result, when magnetic underwater vehicle is sailingunder the sea, it will generate inductive magnetic flux density which
superimposes onto the earth’s background magnetic field. Hence thechange of spatial magnetic field distribution around the target is formed,
which probably causes the underwater vehicle to be tracked bymagnetic anomaly detection device on the aircraft. Therefore, themagnetic stealth characteristic of underwater vehicle draws more andmore country’s attention in the last two decades.
Wang (2012) proposes an underwater large target detection method
based on magnetic anomaly detection and gradient anomaly detection.
Zhou (2018) establishes a submarine magnetic field model using
boundary elements method for aeromagnetic anomaly detection. Zhou(2018) researches on magnetic signature at high altitude for submarine
based on two dimensional Fourier transform and analyzes the magnetic
signature of the spatial distribution in the spatial domain and thefrequency domain. Zhou (2009) proposes a new magnetic field

The magnetostatic field can be calculated by the following two
Maxwell's equations.
∇×� =�∇⋅�=0

(1)
(2)

with the following constitutive (material) relationship being also987