# Model Animations

Animating a solution to a physical problem can be very helpful in understanding the underlying physical phenomena. Sometimes such animations can give rise to new questions and inspire creativity.

The model animations on this page are selected in order to reflect a wide-range of research areas and applications that COMSOL Multiphysics can be used to model.

They come from existing models that you can investigate in detail in the Model Gallery.

### Contact Analysis of a Valve Cap

This model performs a transient contact analysis of a valve cap intended to protect valves from dust and other contaminates. The Structural Mechanics Module in COMSOL was used to simulate the displacements and stresses in the cap during closing.

### Boiling Water

This model studies the film boiling of water. A heat flux above the Leidenfrost point is applied at the surface of two cavities. A layer of vapor is maintained at the hot surface-liquid interface where film boiling results.

### Two Phase Fluid-Structure Interaction

In this animation, a heavy fluid forms a dam, which breaks suddenly, inducing movement in a rubber obstacle. The rubber obstacle's movements then change the fluid's path. The model uses the Phase-Field model to take into account the two-phase flow.

### Simulation of a Microrobot

This example shows the model of one of the legs of a silicon microrobot. Heat is generated by an electric current flowing through the leg and, due to thermal expansion and different thermal expansion coefficients of the leg's materials, a bending action is induced.

### Free Convection in a Cold Water Glass

This example considers the natural convection of a glass of chilled water that sits on a surface of fixed temperature in an environment at the same temperature. The animation shows the fluidâ€™s velocity in the glass as it heats up over time.

### Acoustic-structure Interaction in a Cylinder Immersed in Water

Liquid or gas acoustic waves coupled to structural objects, such as membranes, plates or solids, are important applications in many engineering fields. Examples of such include loudspeakers, acoustic sensors, nondestructive impedance testing, and medical ultrasound diagnostics of the human body.

### Electroosmotic Micromixer

Passive mixers, common in microfluidics applications, often require very long mixing channels to ensure that the molecular diffusion between the different fluids is adequate. An alternative though is to use electroosmotic effects to achieve a mixing effect, perpendicular to the main direction of the flow, to add to the diffusion effects.

### Deformation of a Thermomechanical Microvalve

In this example, a parametric study shows how an increasing voltage applied to each of the legs leads to an increased temperature, imposing more and more deformation.

### Turbulent Flow around a Truck

The flow field around a truck traveling at high speeds is of special interest not only for performance reasons, but also for economical and environmental reasons. For example an extra stack of lights at the top of the vehicle can increase the fuel consumption quite a lot.

### The Electromagnetic Fields from a Railgun

A Railgun is a type of magnetic accelerator gun that utilizes an electromagnetic force to propel an electrically-conductive projectile. Current flowing through the rails sets up a magnetic fields perpendicular to each other, forcing the projectile to accelerate along the rails.

### Solidification of a Molten Aluminum Droplet on a Cold Surface

In the production of metals, there are many instances in which multiphase and free-surface flows with interfacial phenomena are present.

### Contact Analysis of a Snap Hook Fastener

Fasteners like this are common in the automotive industry, for example in the control panel of a car. In this case it is important to know the force that must be applied in order to place the hook in the slot, as well as the force needed to remove it.

### Plastic Deformation During the Expansion of a Stent

This model studies the deformation of a stent subjected to a radial outward pressure using an elasto-plastic material model with linear hardening. The animation shows the total displacement and illustrates both the non-uniform expansion and foreshortening of the stent.

### Droplet Breakup in a T-Junction

Emulsions consist of small liquid droplets immersed in an immiscible liquid and widely occur in the production of food, cosmetics, fine chemicals, and pharmaceutical products.

### Air flow in a Cyclone Separator

A cyclone separator is a common device for separating small particles from a gas stream. The swirling flow introduces centrifugal forces on the particles so that they eventually hit the cyclone wall, lose momentum and fall down; whereas the cleaned gas leaves the cyclone separator through a central pipe.

### Porous Reactor with Injection Needle

This example shows the mixing of reactants and the catalytic reaction rate in a packed bed reactor where one of the reactants is injected through a needle in a perpendicular direction to the main axis of the reactor.

### Self-contact in a Gear Stick Rubber Boot Seal

Boot seals are used in automotive applications to protect moving parts from dust and the like, especially in steering knuckles and suspension components. The sealing material is often required to handle large deformations and sometimes fold in on itself causing self-contact.

### Residence Time in a Turbulent Baffled Reactor

Baffled reactors are common in the water treatment industry and are used to allow for slow reactions to reach completion in as small reactor-volume as possible. Yet, such reactors must be optimized as too much baffling can create unnecessary pressure drops, while too little can lead to 'short-circuiting'.

### Dynamics of a Generator

This example shows how the circular motion of a rotor with permanent magnets in a generator results in an induced EMF in the stator winding. The generated voltage is calculated as a function of time during the rotation.

### Mixing in a Static Mixer

In static mixers, a fluid is pumped through a pipe containing stationary blades. This mixing technique is particularly well suited for laminar flow, and is demonstrated in this animation.

### Two-phase flow from an inkjet

This example demonstrates the modeling of two-phase flow occurring when a droplet is shot from an inkjet printer. The droplet shape and velocity magnitude surrounding the droplet are calculated.

### Fluid-Structure Interaction

This example illustrates how fluid flow can deform surrounding structures, while these structures affect the fluid flow in turn.

### Magnetic Field in a Magnetic Levitation Train

A Maglev train works through both the train and track being equipped with repulsive electromagnets to make the train levitate. This model calculates the fields inside the compartment while also simulating the movement of the train as the driving coils alternate polarity.