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.

Model of a Diffuse Double Layer

In the diffuse double layer and within the first few nanometers of an electrode surface, the assumption of electroneutrality is not valid due to charge separation. Typically, the diffuse double layer may be of interest when modeling very thin layers of electrolyte including those in electrochemical capacitors and microelectrodes. This example shows how to couple the Nernst-Planck equations to ...

A Transient Analysis of Freeze-Drying

Freeze-drying, or lyophilization, is a process for drying heat-sensitive substances such as foods, blood plasma, and antibiotics. The wet substance is frozen and then, through sublimation, ice (or some other frozen solvent) is removed in the presence of a high vacuum. This example models the process of ice sublimation in a vial under vacuum-chamber conditions, a test case for many freeze-drying ...

Fully-coupled Physics with Joule Heating, CFD and Chemical Reactions

In this example, a fluid carrying several chemical components is pumped into a detector compartment. A wire in the center of the detector is heated through Joule heating, which is supposed to detect changes in density through convective cooling. However, the higher temperature around the wire causes the ignition of exothermic chemical reactions, which in turn increase the temperature even more. ...

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 ...

Acoustic-Structure Interaction

Liquid or gas acoustics coupled to structural objects such as membranes, plates or solids are important applications in many engineering fields. This model is a general demonstration of an acoustic fluid phenomenon in 3D that is coupled to a solid object. The walls of the solid object are impacted by the acoustic pressure. The frequency response from the solid is calculated, which is then fed ...

Surface Reactions in a Biosensor

A flow cell in a biosensor contains an array of micropillars. The curved side of the pillars are coated with an active material that allows for the selective adsorption of analyte species in the sample stream. The adsorbed species produce a signal that is dependent upon the local concentration at the pillar surfaces. This example investigates the surface concentration distribution in the cell ...

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, ...

Tonpilz Piezo Transducer

The tonpilz (sound mushroom) piezo transducer is a transducer for relatively low frequency, high power sound emission. The transducer consists of piezoceramic rings stacked between massive ends and pre-stressed by a central bolt. The tail and head mass lower the resonance frequency of the device. In this model the frequency response of the transducer when the bolt is not pre-stressed is ...

Microstrip Patch Antenna

The microstrip patch antenna is used in a wide range of applications since it is easy to design and fabricate. The antenna is attractive due to its low-profile conformal design, relatively low cost and very narrow bandwidth. It is known that the antenna impedance will be higher than an accepted value if fed from the edge, and lower if fed from the center. Therefore, an optimum feed point ...

Voltage Induced in a Coil by Moving Magnet

A magnet moving axially through the center of a coil will induce a voltage across the coil terminals. One practical application of this is in shaker flashlights, where the flashlight is vigorously shaken back and forth, causing a magnet to move through a multi-turn coil, which provides charge to the battery. In this model, the motion of a magnet through a coil is modeled, and the induced voltages ...

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