Welcome to the Gallery.
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Images
A soap film illuminated by a monochromatic light source
A trefoil vortex knot in water imaged via light scattering off micro-bubbles
A rendering of a magnetic field whose core is a (5,2) torus knot
A smoke ring traveling through air
A rendering of the flow field around a trefoil vortex knot using the Biot-Savart Law. The raw data appears white while the core and flow field are traced in red and purple respectively
A rendering of the core of a trefoil vortex knot
Trefoil knots of various sizes rescaled and overlayed in different colors
An array of hydrofoils of various geometry and topology
A rendering of data showing the moment before a reconnection event on a trefoil vortex knot
An initially flat sheet adheres to a curved 3D printed bump, but can equilibrate on the surface. As an incision in the sheet grows, the curvature of the sheet governs the fracture phenomenology
Movies
Demonstration of unidirectional waveguide modes in experiment: A single edge gyroscope is excited for five periods at a gap mode frequency. This causes clockwise propagation around the edge.
A single edge gyroscope is excited for five periods at a frequency which is not in the gap. This does not result in an excitation which propagates around the edge.
Demonstration of unidirectional waveguide modes in lattice with irregular boundary: A single edge gyroscope is excited for five periods at a gap mode frequency. The resulting excitation propagates clockwise around the disturbance in the lattice due to the topological nature of the edge modes.
The direction of propagation of edge modes can be controlled by the geometry of the lattice. An excitation propagating clockwise propagates counterclockwise when the unit cell of the lattice deforms from a hexagonal to bow-tie shape.
A honeycomb lattice can support clockwise or counterclockwise propagating modes depending on the degree of deformation. When all angles of the lattice are 90 degrees, there is no bandgap and there are no edge modes.
An initially flat sheet is conformed to a curved 3D printed surface. As an incision in the sheet grows, the curvature of the sheet governs the fracture phenomenology.
Conforming a sheet to a curved surface, such as the cone shown here, kinks a crack at the onset of growth and curves its path.
A vortex ring produced by extruding fluid from a circular orifice imaged using bubbles.
A vortex ring produced by acceleration of a circular hydrofoil imaged using bubbles.
The evolution of a trefoil vortex knot in water viewed front on imaged using bubbles.
The evolution of a three-fold distorted vortex loop in water captured in 3D.
The evolution of a three-fold distorted vortex loop in water captured in 3D rendered in anaglyph 3D.
The evolution of a pair of linked vortex rings in water captured in 3D.
The evolution of a pair of linked vortex rings in water captured in 3D rendered in anaglyph 3D.
The evolution of a trefoil vortex knot in water captured in 3D.
The evolution of a trefoil vortex knot in water captured in 3D, featuring a detailed depiction of a reconnection event.
A detailed video of a reconnection event in a trefoil knot.
The evolution of a trefoil vortex knot in water captured in 3D rendered in anaglyph 3D.
A slowed imaging of the volumetric lasering-scanning used to capture vortex motion in 3D. The panel on the left shows the laser sheet passing over the vortex, while the panel on the right shows the light collected by the camera at the same time, colored according to the depth of the feature.
This video shows the evolution of the magnetic field encoding a trefoil knot. The core magnetic field lines (orange) form a trefoil knot, and stay knotted as the field evolves, while other magnetic field lines (blue) lie on knotted tori (blue) enclosing the core magnetic field lines. The projections of the energy density on the x-y, y-z and z-x planes are shown in the background.
Our 2013 entry to the APS DFD Gallery of Fluid Motion.
The evolution of a trefoil vortex knot through two reconnection events. The frame on the left shows the traced vortex lines evolving, while the graph in the upper right shows the current center-line helicity and the graph on the lower right shows the helistogram for the current shape.
The evolution of a pair of linked vortex rings through two reconnection events. The frame on the left shows the traced vortex lines evolving, while the graph in the upper right shows the current center-line helicity and the graph on the lower right shows the helistogram for the current shape.
From spinning colloidal particles to a chiral fluid. As they spin, our magnetic particles attract and form clusters. These clusters are characterized by a polycrystalline bulk and an edge current.
Particle tracers in the chiral spinner fluid. A line of particles is colored in the first frame. As the fluid evolves in time, the line of particles dissociates, reflecting the fluid nature of the material.
Two clusters coalesce. Two clusters merge into one, whose shape evolves from a dumbbell into an ellipse and finally into a circle, in a way that is reminiscent of liquid droplets. Playback at 30x real time.
Two clusters coalesce. Two clusters merge into one, whose shape evolves from a dumbbell into an ellipse and finally into a circle, in a way that is reminiscent of liquid droplets. Playback at 100x real time.
A droplet impacts a hard wall. A cluster of spinning particles is led to sediment against a hard wall (bottom). Upon impact, the cluster spreads asymmetrically as it rolls on the wall. Playback at 500x real time.
A hole in the spinner fluid collapses. Playback at 30x real time.
A hole in the spinner fluid collapses. Playback at 2093x real time
Flow past a circular obstacle. The spinner fluid is made to flow past an obstacle by tilting the sample. When the fluid reaches the obstacle, it spreads around it asymmetrically. When the layer reaches a threshold thickness, the fluid strip becomes unstable and breaks into droplets. Playback at 500x real time.
Surface waves in a chiral spinner fluid. The boundary of perturbed slab is tracked and shown in the movie in white. As the fluid evolves in time, the perturbations decay and propagate, resulting eventually in a flat boundary.
Droplet intensity in time. Particles are imaged through crossed polarizers. The resulting intensity of each particle depends on its orientation. As the particles rotate in time, their brightness oscillates four times per rotation.
Velocity field in a droplet. Each particle is labeled by an arrow. The size of each arrow represents the magnitude of the instantaneous velocity, and the orientation represents the direction of the velocity vector.
Droplet at a low-friction interface. A nearly-circular cluster of spinning particles is viewed through crossed polarizers as it rotates at an air-water interface. Playback 1/30 real time.
A hydrodynamic instability. Strips of chiral fluid become unstable below a threshold thickness, breaking up into droplets of uniform size. Playback 20x real time.
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