Bullet trains in Japan
When the bullet trains of Japan exit tunnels they create a pressure differential, causing booms heard by residents 400 meters away. In the densely packed urban landscapes from Tokyo to Osaka, such booms were untenable. Relying on his specialized knowledge of birds, Eiji Nakatsu realized the kingfisher beak was designed to move from low density (air) to high density (water). After running many computational simulations, it turned out the shape of kingfisher beak was ideally suited to reduce the pressure buildup in the tunnel that led to the sonic boom. In 1997, the improved aerodynamics from the Kingfisher inspired design, demonstrated 30% less air resistance, a 13% reduction in power use, met all sound requirements and could run the same routes in less time.
Lotus Leaf Pattern
Due to the nanostructure of the lotus leaf’s surface, the lotus leaf is extremely hydrophobic. Water beads on the surface and rolls off, taking dirt and debris with it. This allows the lotus leaf to remain clean in a swampy environment, which is beneficial to the plant.
This research was introduced in the mid-1990s, and now includes applications for: paints, glass coatings, spray-on applications, and outdoor textiles to name a few. Currently, applications are being explored to create barriers between liquids and surfaces, for example on ships hulls, pipeline interiors, and in packaging. As of 2022 over 603 US patents reference Lotus leaf or Lotus effect, showing the depth of penetration of this single bio-inspired design.
Whale Tubercles on Wind Turbines
Prof. Frank Fish in the early 2000’s wondered at why the leading edge of the humpback whales fins had bumps, called tubercles. For years Frank investigated the phenomenon and looked for collaborators. It took Frank seven years, before he meets Phillip Watts at a conference; an aviation engineer who became equally curious when Frank shared his story. They begin collaboratively investigating the properties of the tubercles, and found that these tubercles allowed the whale to turn at much tighter angles without stalling, providing an important advantage as they chase their prey. In computer simulations, Watts recognizes that the tubercles have the effect of both reducing drag and increasing lift, a potentially game changing benefit. They received their first patent in 2013.
When applied to traditional air foils, such as those in fans and wind turbines, these new “tubercular foils” operate more quietly, at higher speeds and with greater efficiency. Early benchmark comparisons show wind turbines with 20% greater efficiency, and cooling fans with 12% greater efficiency; potentially massive gains in multi-billion dollar industries.