# Application Gallery

The Application Gallery features COMSOL Multiphysics® tutorial and demo app files pertinent to the electrical, structural, acoustics, fluid, heat, and chemical disciplines. You can use these examples as a starting point for your own simulation work by downloading the tutorial model or demo app file and its accompanying instructions.

Search for tutorials and apps relevant to your area of expertise via the Quick Search feature. To download the MPH-files, log in or create a COMSOL Access account that is associated with a valid COMSOL license. Note that many of the examples featured here can also be accessed via the Application Libraries that are built into the COMSOL Multiphysics® software and available from the File menu.

### Ground Heat Recovery for Radiant Floor Heating

Geothermal heating is an environmentally friendly and energy efficient method to supply newer and well insulated houses with heat. The investment costs are higher than for gas or oil heating, so there is a need to investigate the possibilities of arranging heat collectors in the subsurface efficiently. This model compares three different pipe arrangements, embedded in the subsurface of the top ...

### 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.

### Acoustics of a Pipe System with 3D Bend and Junction

This tutorial shows how to model the propagation of acoustic waves in large pipe systems by coupling the *Pipe Acoustics* interface to the *Pressure Acoustics* interface. The tutorial is set up in both the time domain and the frequency domain. 1D pipe acoustics is used to model the propagation in the long straight pipe portions. A 3D model of a pipe junction and pipe bend is coupled to the 1D ...

### Organ Pipe Design

The Organ Pipe Designer allows you to study the design of an organ pipe and then play the sound and pitch of the changed design in a user-friendly app. The pipe sound includes the effects of different harmonics with different amplitudes. The organ pipe is modeled using the Pipe Acoustics, Frequency Domain interface in COMSOL Multiphysics. The simulation app allows you to analyze how the first ...

### Insulation of a Pipeline Section

As oil flows through a pipeline section heat is released due to the work of internal friction forces in the fluid. With good insulation of the pipeline, this generated heat can be used to avoid preheating of the oil, despite the fact that it is to be transported in a cold environment over long distances. This model uses the Non-isothermal Pipe Flow interface to set up and solve the flow and ...

### Geothermal Heating from a Pond Loop

Ponds and lakes can serve as thermal reservoirs in geothermal heating applications. In this example, fluid circulates underwater through polyethylene piping in a closed system. The pipes are coiled in a slinky shape and grouped onto sleds. The Non-isothermal Pipe Flow interface sets up and solves the equations for the temperature and fluid flow in the pipe system, where the geometry is ...

### Convective Flow in a Heat Exchanger Plate

This example models flow in a microchannel heat exchanger by coupling a Laminar Flow interface in 3D to a Pipe Flow interface. By the use of the Pipe Flow interface to model the flow in the microchannels the problem size is significantly reduced. This model showcases the Pipe Connection feature that automatically connects a 3D and and Pipe Flow domain.

### Water Hammer

When a valve is closed rapidly in a pipe network it gives rise to a hydraulic transient known as a water hammer. The propagation of these hydraulic transients can in extreme cases cause failures of pipe systems caused by overpressures. This is a model of a simple verification pipe system consisting of a reservoir, a pipe, and a valve. The valve is in this model closed instantaneously.

### Discharging Tank

This tutorial model illustrates how to calculate the pressure drop and initial flow rate in a pipe system connected to water tank. The Pipe Flow interface contains ready to use friction models accounting for the surface roughness of pipes as well as pressure losses in bends and valves.

### Probe Tube Microphone

It is often not possible to insert a normal microphone directly into the sound field being measured. The microphone may be too big to fit inside the measured system, such as for in-the-ear measurements for hearing aid fitting. The size of the microphone may also be too large compared to the wavelength, so that it disturbs the acoustic field. In these cases, a probe tube may be attached to the ...