# 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.

### 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 materialâ€™s molecular structure. Equations for the latent heat of phase changes appear in many texts but their implementation is ...

### 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 ...

### Heating Circuit - new

Small heating circuits find use in many applications. For example, in manufacturing processes they heat up reactive fluids. The device used consists of an electrically resistive layer deposited on a glass plate. The layer causes Joule heating when a voltage is applied to the circuit. The layerâ€™s properties determine the amount of heat produced. This multiphysics example simulates the ...

### Capacitive Pressure Sensor

A capacitive pressure sensor is simulated. This model shows how to simulate the response of the pressure sensor to an applied pressure, and also how to analyze the effects of packing induced stresses on the sensor performance.

### 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.

### Three-Cylinder Reciprocating Engine

In this example, a dynamic analysis of a three-cylinder reciprocating engine is performed to investigate stresses generated during operation, thereby permitting identification of the critical components. Demand for high power output relative to the weight of the engine requires careful design of its components. This model of a reciprocating engine contains a combination of rigid and flexible ...

### Two-Phase Flow in Porous Media

The first model describes the simultaneous flow of two immiscible fluids in porous media - here air displaces water in a multi-step inlet pressure experiment. We solve for the pressure and the degree saturation for the air and water within a representative volume and so track saturation levels rather than estimating a discrete location for the air-water interface. A second example is also ...

### Optical Scattering off of a Gold Nanosphere

This model demonstrates the calculation of the scattering of a plane wave of light off of a gold nanosphere. The scattering is computed for the optical frequency range, over which gold can be modeled as a material with negative complex-valued permittivity. The far-field pattern and the losses are computed.

### 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.

### Laminar Flow in a Baffled Stirred Mixer

This model exemplifies the use of the Rotating Machinery interface, which allows you to model moving rotating parts in, for example, stirred tanks, mixers, and pumps. The Rotating Machinery interface formulates the Navier-Stokes equations in a rotating coordinate system. Parts that are not rotated are expressed in the fixed material coordinate system. The rotating and fixed parts need to be ...