Birds gliding through helium bubbles reveal an aerodynamic trick

A cloud of tiny helium-filled soap bubbles hovers in the air. When a barn owl glides through them, the bubbles are illuminated and recorded. The experiment is repeated with a tawny owl and a northern goshawk. With this setup, researchers can see, track, and analyze the vortices in each bird’s wake.

Watch birds of prey as they glide through helium bubbles and learn more about the aerodynamics of flight. From Nature:

Researchers in London have discovered a new way in which birds use their tail to provide lift and so reduce drag while gliding. They tracked the swirling motion of more than 20,000 helium-filled soap bubbles as they were displaced by birds of prey in flight. Their findings could provide a new way to improve the efficiency of small gliding aircraft.

More from the Royal Veterinary College in London:

Professor Richard Bomphrey, co-author of the paper, said: “Our understanding of birds in flight was used to generate the very earliest aircraft designs. Since then, aeronautical engineering has led to aircraft that are larger and faster – where the viscosity of air becomes less important – and birds have been left trailing in their wake. Now, though, as our attention turns back to smaller and more efficient vehicles, it seems that birds might have a new relevance to future aeronautics.”

File under biomimicry, fluid dynamics, aerodynamics, flying, and vortices. Then watch these related videos next:
• Wake vortex in the fog as an airplane lands
• Wingtip vortices made visible with ribbons of white smoke
• A vortex of bubbles twirls pufferfish
• The physics of why birds fly in V-formation
• How to make an Air Surfing Foam Walkalong Glider

via @sohkamyung.