Supercomputer simulations at University of Osaka reveal how large scale vortices power dolphin speed

University of Osaka researchers use numerical simulations to reveal how large-scale vortices drive dolphin propulsion and underwater efficiency.

By: AXL Media

Published: Apr 28, 2026, 9:32 AM EDT

Source: Information for this report was sourced from EurekAlert!

Deciphering the Hydrodynamic Efficiency of Marine Mammal Propulsion

Scientists at the University of Osaka have deployed high powered supercomputer simulations to solve the long standing mystery of how dolphins maintain such remarkable speed and agility. By visualizing the complex interactions between animal movement and water, the research team identified that the flapping motion of a dolphin's tail creates a sophisticated hierarchy of swirling currents. These findings, recently published in Physical Review Fluids, provide a quantitative look at how biological locomotion can optimize fluid displacement for maximum forward thrust.

The Mechanics of Oscillating Tails and Underwater Thrust Generation

When a dolphin engages in a vertical kicking motion, it forces water backward and initiates a turbulent flow characterized by vortices of varying magnitudes. Lead author Yutaro Motoori explained that the primary goal was to isolate which specific components of this chaotic turbulent flow actually assist in speed. The simulation data suggests that as the tail moves, it generates powerful, large scale vortex rings that act as the engine for the animal's movement, creating the pressure necessary to propel the body through the water.

The Energy Cascade and the Role of Minor Turbulent Currents

The research successfully mapped a process known as the energy cascade, where larger vortices naturally break down into a series of smaller ones. Senior author Susumu Goto noted that while these smaller vortices are extremely numerous within the wake of the dolphin, they are essentially byproducts of the flow rather than active contributors to speed. This distinction is vital for understanding biological efficiency, as it proves that the dolphin’s physiological energy is effectively channeled into the most impactful hydrodynamic structures.