The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

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Optimizing Coils

Several different approaches to optimizing a ten-turn axisymmetric coil are presented. First, the current in each turn is adjusted with the objective of having a uniform magnetic flux density along the centerline. Second, the currents are adjusted to minimize power dissipation with a constraint on field minimum at a point. Third, the currents are adjusted to minimize the gradient in the ...

Iron Sphere in a 20 kHz Magnetic Field

An iron sphere is exposed to a spatially uniform, sinusoidally time-varying, background magnetic field. The frequency of the field is such that there skin depth is smaller than the sphere radius. The induced currents in the sphere and the perturbation to the background field are computed. Proper meshing of domains with significant skin effect is addressed.

Generator in 3D

This model is a static 3D simulation of a generator having a rotor with permanent magnets. The center of the rotor consists of annealed medium carbon steel, which is a nonlinear ferromagnetic material that is saturated at high magnetic flux densities. The core is surrounded by several blocks of a permanent magnet made of samarium and cobalt, creating a strong magnetic field. The stator is made ...

Tubular Permanent Magnet Generator

This tutorial shows how to model the tubular permanent magnet generator in 2D axisymmetry. The generator consists of a modular stationary stator and moving/oscillating slider. The stator is made of three-phase multiturn windings and an iron core. The slider is made of permanent magnets and iron spacers. The open circuit voltage in the three-phase stator windings due to the periodic motion of the ...

Magnetic Signature of a Submarine

A vessel traveling on the surface or under water gives rise to detectable local disturbances in the Earth’s magnetic field. These disturbances can be used to trigger weapon systems. The magnetic signature of a ship can be reduced by generating a counteracting magnetic field of suitable strength and direction based on prior knowledge of the magnetic properties of the vessel. This model ...

Electrodynamic Bearing

This model illustrates the working principle of a passive electrodynamic bearing. An electrically conducting rotor rotating in a magnetic field produced by a permanent magnets induces eddy currents on the conducting rotor. The eddy currents, in turn, produce a magnetic field that opposes the magnetic fields by the magnets and induces a force that opposes the motion of the rotor. The radial ...

Quadrupole Mass Spectrometer

The principle component of a quadrupole mass spectrometer is the mass filter which is used to filter ions with different charge to mass ratios. The quadrupole mass filter has been well studied over the years, Ref. 1 and the physics and optimal design are well understood. In a real quadrupole mass spectrometer, fringe fields exist at both the entrance and exit of the mass filter. These fringe ...

Electromagnetic Plunger with Stopper

This is a transient model of an electromagnetic plunger with stopper restricting the linear motion. The model consists of a magnetic core, nonmagnetic guider, multi-turn coil, nonmagnetic stopper/blocker, and magnetic plunger attached to the spring and damper at the far end. The electromagnetic force on the plunger due to the transient current in the coil is calculated using the Maxwell stress ...

Magnetically Permeable Sphere in a Static Magnetic Field

A sphere of relative permeability greater than unity is exposed to a spatially uniform static background magnetic field. Two formulations are used to solve this problem, and the differences between these are discussed. The field strength inside the sphere is computed and compared against the analytic solution.

Effective Nonlinear Magnetic Curves Calculator

The Effective Nonlinear Magnetic Curves Calculator application is a companion to the *Effective Nonlinear Constitutive Relations* functionality. Magnetic-based interfaces in the AC/DC Module support the Effective HB/BH Curve material model that can be used to approximate the behavior of a nonlinear magnetic material in a frequency domain simulation without the additional computational cost of a ...