How dorsal fins make fish faster and more efficient
The dorsal and anal fins of fish interact with the tail fins to produce higher thrust and efficiency. We focused on thin elongated dorsal fins, like those of jackfish. We …
Modeling lateral station-keeping in fish
Fish flap their tails asymmetrically to maneuver around obstacles. In contrast, classic fish tail models assume symmetric motions in a uniform flow. We tested how well these classic models work …
Stable equilibria exist for near-surface swimmers and fliers
Fish and birds experience different forces when they swim/fly near a flat surface (e.g. seabed, solid ground, still lake). We discovered that the vertical forces they feel switch from negative …
Scaling laws for 3D pitching hydrofoils
Building on our previous work on 2-D pitching airfoils, we explored how forces and torques scale for 3-D pitching airfoils. The terms we added to existing theories were inspired by …
Scaling laws for 2D pitching hydrofoils
Modeling the forces and torques on 2-D pitching airfoils is critical for understanding the locomotion of fish and birds. Traditional linear theories can predict some of the forces, but break …
Ninsinusoidal swimming/flying gaits
Existing studies of fish and bird locomotion typically assume the fins/wings oscillate sinusoidally. We explored what happens when the oscillations range from triangle waves to square waves. Triangle waves behave …
Optimizing the efficiency of flexible swimming panels
Simplified geometries can be used to isolate the effects of flexibility in swimming fish. Here we used an oscillating flexible rectangular panel to explore how efficiency is affected by frequency, …
Side-by-side propulsors show high thrust and efficiency when tuned properly
When fish swim in a school, they interact hydrodynamically with one another. We explored these interactions by testing two rigid pitching airfoils side-by-side in a water channel. We found that …
Flexible panels produce more thrust near solid boundaries
We extended our work on rigid airfoils and discovered that flexible panels also produce more thrust near a solid boundary. This time, we checked swimming speed directly and confirmed that …
Pitching airfoils produce more thrust near solid boundaries
Airplanes gliding near the ground experience experience a boost in lift. We discovered that this boost extends to unsteady lift forces, such as those governing thrust production in fish. Fish …
Scaling the efficiency of flexible swimming panels
Simplified geometries can be used to isolate the effects of flexibility in swimming fish. Here we used an oscillating flexible rectangular panel to explore how efficiency scales with panel stiffness …