Buoyancy Flow of 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 ...
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.
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 Field of a Helmholtz Coil
A Helmholtz coil is a parallel pair of identical circular coils spaced one radius apart and wound so that the current flows through both coils in the same direction. This winding results in a uniform magnetic field between the coils with the primary component parallel to the axes of the two coils. Applications of Helmholtz coils range from canceling the earth’s magnetic field to generating ...
Red Blood Cell Separation
Dielectrophoresis (DEP) occurs when a force is exerted on a dielectric particle as it is subjected to a nonuniform electric field. DEP has many applications in the field of biomedical devices used for biosensors, diagnostics, particle manipulation and filtration (sorting), particle assembly, and more. The DEP force is sensitive to the size, shape, and dielectric properties of the particles. ...
Heating Circuit
Small heating circuits find use in many applications. For example, in manufacturing processes, they heat up reactive fluids. The device in this tutorial example consists of an electrically resistive layer deposited on a glass plate. The layer results in Joule heating when a voltage is applied to the circuit, which results in a structural deformation. The layer’s properties determine the amount ...
Transport and Adsorption
This model demonstrates how to model phenomena defined in different dimensions in a fully coupled manner using COMSOL Multiphysics. Whereas in most cases the reaction rate expression is defined as a function of the concentrations of the reactants and products, in adsorption reactions it is also necessary to model the surface concentrations of the active sites or surface complex. This implies ...
Fluid-Structure Interaction in a Network of Blood Vessels
This model refers to a portion of the vascular system of a young child - the upper part of the aorta artery. The blood vessels are embedded in a biological tissue (the cardiac muscle) and, during the flow of blood, pressure is applied to the internal surfaces producing deformation of the vessel walls. The complete analysis consists of two distinct but coupled procedures: a fluid-dynamics ...
Dielectric Slab Waveguide
A planar dielectric slab waveguide demonstrates the principles behind any kind of dielectric waveguide such as a ridge waveguide or a step-index fiber. This model solves for the effective index and fields of a dielectric slab waveguide and compares the solution to analytic results.
Rock Fracture Flow
A potential flow model of fluid flow in a rock fracture uses the so-called Reynolds equation. It shows how to use experimental data interpolated to a function used in the equation.