# Application Gallery

The Application Gallery features COMSOL Multiphysics tutorial and demo app files pertinent to the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use tutorial models and demo apps with step-by-step instructions for how to create them yourself. The examples in the gallery serve as a great starting point for your own simulation work.

Use the Quick Search to find tutorials and apps relevant to your area of expertise. Log in or create a COMSOL Access account that is associated with a valid COMSOL license to download the MPH-files.

### Computing the Resistance of a Wire

Every electrical device has some resistance. That is, when a voltage difference is applied across any two terminals of the device, there will be a directly proportional current flow. This model demonstrates how to compute the resistance of a short section of copper wire. The convergence of the solution with respect to the mesh size is also studied.

### Inductor in an Amplifier Circuit

This model shows how to combine an electric circuit simulation with a finite element simulation. The finite element model is an inductor with a nonlinear magnetic core and 1000 turns, where the number of turns is modeled using a distributed current technique. The circuit is imported into COMSOL Multiphysics as a SPICE netlist, which merges the inductor model and the circuit elements as ODEs.

### Mutual Inductance and Induced Currents Between Single-Turn Coils

The mutual inductance between a primary and secondary single turn coil in a concentric coplanar arrangement is computed using a DC, steady-state, model and compared against the analytic solution. The induced currents in the secondary coil are computed using an AC, frequency-domain, analysis. The relationship between the AC induced currents and the DC inductance is discussed.

### Mutual Inductance and Induced Currents in a Coil Group

The mutual inductance and induced currents between a single turn primary and twenty turn secondary coil in a concentric coplanar arrangement is computed using a frequency domain model. Each turn of the secondary coil is modeled explicitly. The results are compared against analytic predictions.

### 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 ...

### Rotating Machinery 3D Tutorial

This is a tutorial how to set up electric machinery in 3D using a combination of the magnetic fields and magnetic fields no currents interfaces.

### One-Sided Magnet and Plate

Permanent magnets with a one-sided flux have many uses. The one-sided flux behavior is obtained by giving the magnet a magnetization that varies in the lateral direction. This model shows this technique to model a cylindrical one-sided permanent magnet. A special technique to model thin sheets of high permeability material was used to model a thin metal plate next to the magnet. This ...

### A Geoelectrical Forward Problem

The classical forward problem of geoelectrics (includes electrical resistivity tomography, ERT and earlier techniques as vertical electric sounding, VES) is the calculation of potentials at a given set of electrodes (M,N) while current is injected at other electrodes (A,B) into the ground. Typically the physical domain (earth) is unbounded to the sides and the bottom because of which one needs ...

### Modeling a Spiral Inductor Coil

Spiral inductor coils are attractive because they can be integrated easily while electroplating other printed circuits and provide robust inductance values. Models of such spiral inductors can become quite large as the number of turns increases. This example demonstrates how to exploit the near-symmetry of the structure to greatly reduce the model size. An eight-turn octagonal spiral coil is ...

### Tubular Permanent Magnet Generator

This tutorial example 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 multi-turn windings and 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 ...