Model Gallery

The Model Gallery features COMSOL Multiphysics model files from a wide variety of application areas including the electrical, mechanical, fluid, and chemical disciplines. You can download ready-to-use models and step-by-step instructions for building the model, and use these as a starting point for your own modeling work. Use the Quick Search to find models relevant to your area of expertise, and login or create a COMSOL Access account that is associated with a valid COMSOL license to download the model files.

Mach-Zehnder Modulator

A Mach-Zehnder modulator is used for controlling the amplitude of an optical wave. The input waveguide is split up into two waveguide interferometer arms. If a voltage is applied across one of the arms, a phase shift is induced for the wave passing through that arm. When the two arms are recombined, the phase difference between the two waves is converted to an amplitude modulation. This is a ...

DC Characteristics of a MOS Transistor (MOSFET)

This model calculates the DC characteristics of a simple MOSFET. The drain current versus gate voltage characteristics are first computed in order to determine the threshold voltage for the device. Then the drain current vs drain voltage characteristics are computed for several gate voltages. The linear and saturation regions for the device can be identified from these plots.

Airflow Over an Ahmed Body

The Ahmed body represents a simplified, ground vehicle geometry of a bluff body type. Its shape is simple enough to allow for accurate flow simulation but retains some important practical features relevant to automobile bodies. This model describes how to calculate the turbulent flow field around a simple car-like geometry using the Turbulent Flow, k-epsilon interface. Detailed instructions ...

Phase Change

This example demonstrates how to model a phase change and predict its impact on a heat transfer analysis. When a material changes phase, for instance from solid to liquid, energy is added to the solid. Instead of creating a temperature rise, the energy alters the material’s molecular structure. Equations for the latent heat of phase changes appear in many texts but their implementation is ...

Computing Capacitance in a Comb Drive

Capacitive comb drives are commonly used both as actuators and position sensors. The following model focuses on position measurement. Many approaches exist for positional measurements with MEMS devices, of which capacitance measurement is the most widely used, particularly in micro-accelerometers. In a pair of interdigitated combs the fingers of one comb do not touch those of the other comb, ...

Computing Q-Factors and Resonant Frequencies of Cavity Resonators

A classic benchmark example in computational electromagnetics is to find the resonant frequency and Q-factor of a cavity with lossy walls. Here, models of rectangular, cylindrical, and spherical cavities are shown to be in agreement with analytic solutions.

NOx Reduction in a Monolithic Reactor

This suite of examples illustrate the modeling of selective NO reduction, that occurs as flue gases pass through the channels of a monolithic reactor in the exhaust system of a motored vehicle. The simulations are aimed at finding the optimal dosing of NH3, the reactant that serves as reducing agent in the process. Three different analyses are performed: Kinetic analysis: The example takes a ...

Modeling a Dipole Antenna

The dipole antenna is one of the most straightforward antenna configurations. It can be realized with two thin metallic rods that have a sinusoidal voltage difference applied between them. The length of the rods is chosen such that they are quarter wavelength elements at the operating frequency. Such an antenna has a well known torus-like radiation pattern.

Sloshing Tank

Transport of large quantities of fluid can happen in unstable environments. A perfect example is an oil tanker on the high seas. This model uses ALE for an incompressible Navier-Stokes problem with a free surface. This models the fluid with its original mesh, but allows the mesh to deform according to the fluid’s ‘deformation’. This requires that the position of the mesh and its nodes ...

Cooling of an Injection Mold

This model shows how you can use the Non-Isothermal Pipe Flow interface together with the Heat Transfer in Solids interface to model the cooling of a injection molded polyurethane part for a car steering wheel. The equations describing the cooling channels are fully coupled to the heat transfer equations of the mold and the polyurethane part.

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