# Galleria dei Modelli

La Galleria dei Modelli raccoglie un'ampia varietà di modelli realizzati con COMSOL Multiphysics in diversi ambiti applicativi, inclusi quelli elettrico, meccanico, fluidico e chimico. E' possibile scaricare i file .mph dei modelli pronti all'uso e le istruzioni step-by-step per costruirli, e utilizzarli come punto di partenza per le proprie simulazioni. Lo strumento di Ricerca Rapida permette di trovare i modelli che si riferiscono alla propria area di interesse. Per scaricare i file .mph dei modelli è necessario effettuare il login o creare un account COMSOL Access associato a un numero di licenza valido.

### 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 or ...

### Buoyancy Flow in Free Fluids

This model couples the Navier Stokes equations and the heat transfer equations to examine density driven flow of free fluids. Here the fluid is in a square cavity with a heated wall. The buoyancy force is a Boussinesq term added to the Navier-Stokes equations. The equation is nondimensionalized, so the material coefficients are set up using Rayleigh and Prandtl numbers. The parametric solver ...

### Thin-Layer Diffusion

This tutorial model demonstrates the use of brick and prism meshes to mesh thin 3D structures. An identity boundary condition makes sure that the concentration is the same across the interface between the two geometries. Connecting two different mesh types is a good way for saving memory in geometries with large aspect ratios. In this example, the curved geometry requires greater resolution ...

### Thin Film Resistance

In modeling of transport by diffusion or conduction in thin layers, we often encounter large differences in dimensions of the different domains in a model. If the modeled structure is a so-called sandwich structure, we can replace the thinnest geometrical layers with a thin layer approximation, provided that the difference in thickness is very large. This method can be used in many ...

### Magnetic Drug Targeting

Current research on methods to target chemotherapy drugs in the human body includes the investigation of biocompatible magnetic nanocarrier systems, for example magnetic liquids such as ferrofluids. This model investigates an external magnetic field and its interaction with blood flow containing a magnetic carrier substance. The model is based on the Maxwell and Navier-Stokes equations, where a ...

### 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.

### 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 ...

### Shallow Water Equations

The Shallow Water equations are frequently used for modeling both oceanographic and atmospheric fluid flow. Models of such systems lead to the prediction of areas eventually affected by pollution, coast erosion and polar ice-cap melting. Comprehensive modeling of such phenomena using physical descriptions such as the Navier-Stokes equations can often be problematic, due to the scale of the ...

### Axisymmetric Transient Heat Transfer - new

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.

### Using Meshing Sequences

COMSOL Multiphysics provides an interactive meshing environment where, with a few mouse clicks, you can easily mesh individual faces or domains. Each meshing operation is added to the meshing sequence. The final mesh is the result of building all the operations in the meshing sequence. This example demonstrates how to use the meshing sequence to create a mesh consisting of different element ...