Modell Galerie

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.

Slip Flow Benchmark

This model is a benchmark model for the Slip Flow interface. It is based on both analytic and numeric calculations. Air at atmospheric pressure flows through a conducting micro-channel connecting two reservoirs maintained at different temperatures. A flow between the two reservoirs develops as a result of thermal creep along the channel wall, which in turn produces a pressure gradient. At steady ...

Split-Recombine Mixer Benchmark

This example models a split and recombine mixer channel in which a tracer fluid is introduced and mixed by multi-lamination. Diffusion is removed from the model using an extremely low diffusion coefficient so that any numerical diffusion can be studied in the lamination interfaces. The results compare well with Glatzel et al (Ref 1.) in both the lamination patterns and total pressure drop ...

AC Electrokinetically Enhanced Surface Reactions

This model studies the use of AC electrokinetic forces to enhance the rate of transport of electrolytic reactants to a reaction surface on the wall of a microchannel. If transport was to be governed by flow alone, then the flow velocity perpendicular to the surface would be so small that the analyte would be transported mainly by diffusion. The reaction rate at the surface is large enough ...

Electrokinetic Valve

This model presents an example of pressure driven flow and electrophoresis in a 3D micro channel system. Researchers often use a device similar to the one in this model as an electrokinetic sample injector in biochips to obtain well-defined sample volumes of dissociated acids and salts and to transport these volumes. Focusing is obtained through pressure driven flow of the sample and buffer ...

Electroosmotic Flow in a Biochip

Miniature laboratories are required to efficiently analyze the information in human DNA. Such laboratories could facilitate tailor-made diagnoses and treatment of hereditary diseases for each individual. One problem that arises in these lab-on-a-chip devices lies in the transport of the liquid samples and other solutions, which move very small channels. One way of transporting the fluid in ...

Jet Instability - Moving Mesh and Level Set Models

The Marangoni effect results in a slip velocity in the tangential direction on a fluid/fluid interface due to gradients in the surface tension coefficient. When the surface tension coefficient is constant, a two-fluid system may exist in static equilibrium. This is because the surface tension force may be exactly balanced by a jump in the pressure across the interface. The pressure is ...

Viscous Catenary

The catenary is the geometrical shape that corresponds to the curve followed by an idealized chain or cable supported at both ends and hanging under its own weight. The viscous catenary problem describes the motion of a cylinder of highly viscous fluid, supported at its ends as it flows under gravity. In the last decade this problem has generated significant theoretical and experimental interest ...

Knudsen Minimum

When a constant pressure difference drives flow through a narrow constriction between parallel plates (or through a cylindrical tube), the flow rate exhibits a characteristic minimum as the absolute pressure at the inlet is reduced. This phenomenon is commonly referred to as Knudsen’s minimum, and occurs as a result of the rarefaction of the gas. The observation of a minimum in flow rate for ...

Oscillating Droplet

Cemented tungsten carbides are hard metals used in steel cutting tools. They are produced by heating a powder consisting typically of tungsten carbide (WC) grains and cobalt (Co) grains. When the powder is heated, the cobalt melts but the tungsten carbide remains solid. The liquid cobalt glues the tungsten carbide grains together and forces air to flow out of the material. When the medium is ...

Electroosmotic Micropump

Micropumps, especially those based on electroosmotic flow (EOF), are essential components in microfluidic lab-on-a-chip devices, as they contain no moving parts and are relatively easy to integrate in microfluidic circuits during fabrication. One major drawback in the conventional design of electroosmotic micropumps is the use of a high driving voltage. Therefore, the development of a ...

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