Sharkskin structure or help airplanes fly faster

 Sharkskin structure or help airplanes fly faster

Reference News Network reported on March 6, according to the British Times website reported on March 5, sharks swimming in water principle, showing how the aircraft to adapt to airflow flight.

According to the report, no one knows the fastest speed of mackerel shark. According to some accounts, it can reach a speed of 30 miles per hour (about 48 kilometers). Others say that mackerel sharks feed on tuna, which can travel at 45 miles per hour (about 72 kilometers per hour), so mackerel sharks may be almost twice as fast as tuna.

Researchers have studied why mackerel sharks swim so fast. They tested the skin of mackerel sharks, confirming a long-standing assumption that the bristles of sharks act as pits on the surface of golf balls. Researchers hope the research, funded by Boeing and the U.S. military, will help airplanes fly faster.

Gray mackerel shark

A major source of air resistance is boundary layer separation. When an object moves, it has a nearly static layer of water or air attached to its surface. This phenomenon occurs when the object is dragged backwards. A pit in a golf ball can break this boundary layer and allow the ball to fly farther.

A team of aeronautical engineers removed several pieces of mackerel shark skin and placed them in flowing water for research. They found that the 0.2mm bristles covering the sharks body had a similar effect.

In the experiment, the researchers placed a smooth surface in a tank, then a shark skin, and then measured the flow in both cases. The results were presented at the annual meeting of the American Physical Society. Amy Lan, of the University of Alabama, said: In all cases involving shark skin, we found that the area of the mobile separation zone was significantly reduced by shark skin.

They know that this angular bristle (inspired by the revolutionary Speedbillo swimsuit) prevents boundary layer separation. From one point of view, the skin is very smooth, but from another point of view, the skin is like sandpaper. This prevents backflow. This means that it is much more difficult for the boundary layer to divert and generate resistance.

Interestingly, Amy Lan says, skin produces this effect without active shark control. The prospect that artificial surfaces can use this completely passive mechanism even in the air is very exciting, she said.

Source: Reference Message Network Responsible Editor: Zhang Fan_NBJS7849