Japan's fastest supercomputer has just achieved a windy breakthrough. Researchers at Nagoya University have conducted simulations of air turbulence occurring on clear days around Tokyo using the country's fastest computer.
The team used their findings to make a more accurate predictive model while comparing it to flight data.
Supercomputer in Japan Used to Simulate Winds
Air turbulence can be bothersome during flights as it makes the airplane cabin shake even on a sunny and cloudless day. Although air turbulence is typically linked with inclement weather, it can also occur on clear, sunny days.
These turbulent air movements, known as clear air turbulence (CAT), can happen even when there are no apparent clouds or other meteorological disturbances.
Although the precise causes of CAT are not well known, wind shear and atmospheric instability are thought to be the main contributors.
CAT presents a serious threat to aviation security. On an otherwise quiet day, the abrupt turbulence can cause injury to passengers and crew, damage the aircraft, and interfere with flight operations.
Therefore, researchers can better comprehend CAT by utilizing large-eddy simulation (LES), a computational fluid dynamics method used to mimic these turbulent flows.
However, researchers noted that one of the biggest problems with LES is the computing cost, despite its significance to research on air turbulence. High levels of processing power are needed to simulate the intricate interactions involved in LES.
The research team used the Fugaku supercomputer, an exascale computer, to intricately mimic the process of turbulence creation using high-resolution LES. It is a high-performance computing machine and is currently the second-fastest supercomputer in the world.
Ultra-High-Resolution Simulation
The researchers carried out an ultra-high-resolution simulation of the CAT over the Haneda airport in Tokyo during the winter, which was brought on by low pressure and a nearby mountain range.
They discovered that the Kelvin-Helmholtz instability wave, a particular kind of instability that happens at the interface between two layers of air with different velocities, was responsible for the disturbance in wind speed.
After performing their calculations, the team sought to verify that their simulated vortices matched with actual data. In a statement, Dr. Ryoichi Yoshimura of Nagoya University noted that there is enough observational data available in the Tokyo area to support their findings.
Yoshimura added that "there are many airplanes flying over the airports, which results in many reports of turbulence and the intensity of shaking."
The team has also used atmospheric observations by a balloon close to Tokyo. The computations were validated using the shaking data that had been recorded at that time.
"The results of this research should lead to a deeper understanding of the principle and mechanism of turbulence generation by high-resolution simulation and allow us to investigate the effects of turbulence on airplanes in more detail," Yoshimura said.
"Since significant turbulence has been shown to occur in the limited 3D region, routing without flying in the region is possible by adjusting flight levels if the presence of active turbulence is known in advance. LES would provide a smart way of flying by providing more accurate turbulence forecasts and real-time prediction," Yoshimura added.
The findings of the team were published in the journal Geophysical Research Letters.
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