Shark Skin Study Reveals Insights For Enhancing Aircraft And Boat Efficiency

Researchers from Tokyo Institute of Technology have uncovered details about how great white sharks reduce drag, which could lead to advancements in aircraft and boat design. Their study explores how the shark’s unique skin structures—known as dermal denticles—play a key role in minimizing friction as the shark swims at various speeds.

The great white shark’s skin is covered with tiny tooth-like structures that help it move efficiently through water. These denticles vary in shape, size, and spacing, allowing the shark to maintain high speeds while hunting and to cruise long distances with minimal energy expenditure.

Previous research has used shark denticles as inspiration to develop riblets—small, unidirectional ridges—for aircraft and sailboats. However, Tokio Tech News reports that the variation in shape, size, and spacing of denticles across a shark’s body complicates the understanding. This variation makes it challenging to fully grasp how these factors collectively impact drag reduction.

This new study highlights how different ridge heights on these denticles contribute to this drag reduction. High middle ridges are particularly effective at slower speeds, aiding in efficient cruising, while lower side ridges become more important during high-speed hunting bursts.

By developing 3D models of these denticles, the Tokyo Tech team was able to analyze how the ridges’ height and spacing impact drag reduction. Their findings suggest that the combination of high and low ridges allows the shark to handle a wide range of swimming speeds efficiently.

Associate Professor Hiroto Tanaka, the study’s lead author, explains, “Our calculations suggest that the combination of high and low ridges of the denticles results from adapting to both slow and high swimming speeds, thereby offering robustness to various swimming conditions”

The researchers used a microfocus X-ray CT scanner. This scanner created detailed 3D models of the denticles. They then analyzed these models to understand how the denticles’ design affects drag reduction. The study builds on earlier fluid dynamics research. This research showed that the denticles’ ridges help lift turbulent vortices away from the shark’s skin. As a result, friction drag is reduced.

Tanaka further notes, “High ridges likely reduce drag at low swimming speeds, and high-low alternating ridges reduce drag at high swimming speeds, covering the full range of swimming speeds. Our calculation method also can be applied to other sharks including extinct species.”

This research not only highlights the efficiency of modern sharks, but also opens up potential for innovation in engineering fields. By mimicking the denticle structures found in sharks, engineers can design riblets for aircraft and boats that reduce drag and improve performance, much like how sharks achieve optimal swimming efficiency.