# 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.

### Axisymmetric Transient Heat Transfer

This is a benchmark model for an axisymmetric transient thermal analysis. The temperature on the boundaries changes from 0 degrees C to 1000 degrees C at the start of the simulation. The temperature at 190 s from the anlysis is compared with a NAFEMS benchmark solution.

### Marangoni Convection

Marangoni convection occurs when the surface tension of an interface (generally liquid-air) depends on the concentration of a species or on the temperature distribution. In the case of temperature dependence, the Marangoni effect is also called thermo-capillary convection. The Marangoni effect is of primary importance in the fields of welding, crystal growth and electron beam melting of ...

### Diffraction Patterns

This example resembles the well-known 2-slit interference experiment often demonstrated in schools with water waves or sound. This model mimics the plane-wave excitation with two thin waveguides leading to slits in a screen, and it computes the diffraction pattern on the screen’s other side. This diffraction pattern is clearly visible. The main effect of quantization is that the numerical ...

### Loaded Spring - Using Global Equations to Satisfy Constraints

Global equations are a way of adding an additional equation to a model. A global equation can be used to describe a load, constraint, material property, or anything else in the model that has a uniquely definable solution. In this example, a structural mechanics model of a spring is augmented by a global equation which solves for the load to achieve a desired spring displacement.

### Conical Quantum Dot

Quantum dots are nano- or microscale devices created by confining free electrons in a 3D semiconducting matrix. Those tiny islands or droplets of confined “free electrons” (those with no potential energy) present many interesting electronic properties. They are of potential importance for applications in quantum computing, biological labeling, or lasers, to name only a few. Quantum dots can ...

### Micromixer

The development of mixers does often not only have to account for effectiveness, but also other factors must be involved, such as cost and complexity for manufacturing. The three models study a laminar static micro mixer with two parallel sets of split-reshape-recombine mixing elements. The mixer works through lamination of the streams without any moving parts and the mixing is obtained through ...

### Micromixer - Cluster Version

This example studies a laminar static micromixer with two parallel sets of split-reshape-recombine mixing elements. The mixer works through lamination of the streams without any moving parts and the mixing is obtained through diffusion. The purpose of this model is to demonstrate how to access the cluster computing functionality in COMSOL from COMSOL Desktop and use it to submit a batch job to ...

### Electrical Signals in a Heart

Modeling the electrical activity in cardiac tissue is an important step in understanding the patterns of contractions and dilations in the heart. The heart produces rhythmic electrical pulses, which trigger the mechanical contractions of the muscle. A number of heart conditions involve an elevated risk of re-entry of the signals. This means that the normal steady pulse is disturbed, a severe and ...

### Process Control Using a PID Controller

This model shows how a flow model can be coupled to a process control mechanism. Controlling application parameters according to other application parameters is important within process engineering. Most control mechanisms use the data at a wall or an outlet to control inlet parameters. More accurate control can occur if you can control inlet parameters due to data found within a component ...

### Steady-State 2D Heat Transfer with Conduction

This example shows a 2D steady-state thermal analysis including convection to a prescribed external (ambient) temperature. It is given as a benchmarking example. The benchmark result for the target location is a temperature of 18.25 C. The COMSOL Multiphysics model, using a default mesh with 556 elements, gives a temperature of 18.28 C. Successive uniform refinements show a temperature of 18.26 ...