Two San Diego State University aerospace engineering researchers developed a new model in computational mathematics that could have widespread implications for hypersonic military aircraft.
The model predicts how fuel droplets and gas particles behave in detonation waves. These waves occur in rocket engines, scramjets, which fly at hypersonic speeds. However, the new model could also have applications for climate science and medicine.
Shedding light on hypersonic flight
Hypersonic flight refers to any speed from Mach 5 and above. That’s five times the speed of sound, or approximately 6,173 km/h (3,836 mph). At those speeds, a missile or rocket could fly anywhere on Earth in less than four hours.
Scientists used to have very little information regarding the paths particles of liquid or gas take in hypersonic flight. Now, the new work sheds light on this, enabling new, advanced systems modeling.
Professor Gustaaf Jacobs and Assistant Professor Qi Wang of SDSU College of Engineering developed the new model in collaboration with Stanford University’s Daniel Tartakovsky.
The team’s work, funded by a grant from the US Air Force Office of Scientific Research, focuses on interacting particle systems. The researchers developed their model for hypersonic aircraft research. It could, for example, shed light on the stability of gases and how they affect engines.
This field of research emerged in the Manhattan Project at Los Alamos, New Mexico, where the first nuclear bomb was developed by J. Robert Oppenheimer and Edward Teller.
“The driver of this is to understand how droplets of fuel that are injected into high-speed propulsion systems such as scramjets or rotating detonation engines – similar to rocket engines that are commonly used to achieve hypersonic flight – interact with shock waves,” Jacobs explained in a press statement.
When things go wrong at Mach 5
Jacobs and Wang referred to their model as the Liouville method, taking after the 19th-century French mathematician and engineer. It builds on the Fokker–Planck equation and the Langevin model, which predicts how particles move in a flow.
The team, who published their findings in the journal Physics of Fluid, built a data-driven model that infers forces from the small amounts of data. Their framework iteratively predicts the locations of particles in relation to specific speed changes over time.
“The thermal behavior – the stability behavior of gas very close to the flying object – is very finicky,” Jacobs said. “Once things go wrong at Mach 5, they go really wrong. That’s when the aircraft stops flying.”
Though the model is mainly designed for hypersonic technologies, it could also help with medicine and environmental science. The physics of climate change involves particle dynamics, and some medical practices, such as one for breaking kidney stones, involve employing shock waves.
Chris Young Chris Young is a journalist, copywriter, blogger and tech geek at heart who’s reported on the likes of the Mobile World Congress, written for Lifehack, The Culture Trip, Flydoscope and some of the world’s biggest tech companies, including NEC and Thales, about robots, satellites and other world-changing innovations.
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