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.

Magnetic Field of a Helmholtz Coil

A Helmholtz coil is a parallel pair of identical circular coils spaced one radius apart and wound so that the current flows through both coils in the same direction. This winding results in a uniform magnetic field between the coils with the primary component parallel to the axes of the two coils. Applications of Helmholtz coils range from canceling the earth’s magnetic field to generating ...

Flow Past a Cylinder

The following model examines unsteady, incompressible flow past a long cylinder placed in a channel at right angle to the oncoming fluid. The cylinder is offset somewhat from the center of the flow to make the steady-state symmetrical flow unstable. The simulation time necessary for a periodic flow pattern to appear is difficult to predict. A key predictor is the Reynolds number, which 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, ...

Laser Heating of a Silicon Wafer - new

A silicon wafer is heated up by a laser that moves radially in and out over time. In addition, the wafer itself is rotated on its stage. The incident heat flux from the laser is modeled as a spatially distributed heat source on the surface. The transient thermal response of the wafer is shown. The peak, average, and minimum temperature during the heating process is computed, as well as the ...

Helicopter Swashplate Mechanism

This model illustrates the operation of a swashplate mechanism used in helicopters to translate the input of helicopter flight control into the motion of the rotor blades, and hence controls the orientation of the rotor blades. In this model, the rotor blades are modeled as either rigid bodies or flexible bodies in two different cases. All other components are assumed to be rigid bodies. Stress ...

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 ...

Impedance Matching of a Lossy Ferrite 3-port Circulator

A lossy ferrite circulator at 3GHz is modeled. Geometrical design parameters are varied to match the impedance for minimal reflection of the fundamental TE10 rectangular waveguide mode.

Forced and Natural Convection Cooling of Circuit Boards

The suite of models examine the air cooling of circuit boards populated with multiple integrated circuits (ICs), which act as heat sources. Two possible cooling scenarios are depicted: vertically aligned boards using natural convection, and horizontal boards with forced convection (fan cooling). In this case, contributions caused by the induced (forced) flow of air dominate the cooling. To ...

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.

Porous Reactor with Injection Needle

This model treats the flow field and species distribution in an experimental reactor for studies of heterogeneous catalysis. The model exemplifies the coupling of free and porous media flow in fixed bed reactors. The reactor consists of a tubular structure with an injection tube that has its main axis perpendicular to the axis of the reactor. The incoming species in the main and injection ...

Quick Search