Researchers develop unified sensor to better control effects of shock waves

September 19, 2019

As a fighter jet quickly ascends and accelerates forward, a sonic boom reverberates across the jet's surface and through the surrounding sound waves. At best, it's unpleasant noise pollution. At worst, it can damage the surface of the aircraft. Dissipating this shock wave presents a tough challenge as traditional methods tend to offer efficiency or precision, but not both.

Now researchers with Yokohama National University in Japan have developed a unified shock sensor to quickly and accurately dispel harmful shock waves. They published their results on July 4 in the Journal of Computational Physics.

"There's a growing need for a simple and accurate shock-detection method in computational fluid dynamics," said Keiichi Kitamura, associate professor of engineering at the Yokohama National University in Japan. But scientists don't want to completely eliminate shocks - not all shocks are bad, after all. When applied correctly, a shock wave can flow through kidney stones and disintegrate the calcified rocks to make them easier for a person to pass. That process requires significantly more accuracy to avoid damaging healthy tissue, but it can be time consuming.

"Shock has been applied to the medical field through Extracorporeal Shock Wave Lithotripsy," Kitamura said. "It's one of the most common treatments for kidney stones in the United States of America. But most of the conventional shock-proofing methods are designed to satisfy only accuracy or efficiency."

"In all cases, it is of great importance to identify the exact location of the shock wave quickly," Kitamura said.

In the new study, researchers combined an imaging processing method with a theory on the expected conditions in compressible flow physics - when fluid flow has compressible effects, such as creating a shock wave when the fluid moves quicker than the speed of sound. This speed is what is responsible for shock.

The researchers altered the imaging processing method to look for pressure instead of discontinuous changes of brightness in digital images. This allows them to quickly see the shock wave. By combining the visualized image of the shock with the theory of how the pressure should jump across the shock, researchers can accurately predict how a specific shock wave will behave. The imaging process method is what Kitamura calls "computationally cheap," since it focuses on just the outlines of greatest pressure, rather than attempting to account for all the variable pressure in the image.

The researchers also compared their method to traditional sensors to test for efficiency and accuracy: the Kanamori-Suzuki sensor and the Ducros sensor. The Kanamori-Suzuki uses the theory of flow characteristics to sense shock and it is known for its accuracy. The Ducros is widely used and known for its inexpensive efficiency.

"In our examples, we confirmed that our method is as accurate at the Kanamori-Suzuki method and as cheap as the Ducros sensor," Kitamura said.

Currently, the method is limited to grids of square cells, which is what the imaging software uses. Next, the team plans to expand their method to apply to a wide array of differently structured grids. This could be applied to a variety of technologies, including improvements in how a jet dissipates shock.

"As this research advances, the shock capturing ability will become more efficient, leading to drastic cost reductions in developing aircraft vehicles and pursuing space developments," Kitamura said.
-end-
Takeshi R. Fujimoto of Yokohama National University and Taro Kawasaki also contributed. Kawasaki is currently with the University of Tokyo but was with Yokohama National University at the time of the research.

Yokohama National University (YNU or Yokokoku) is a Japanese national university founded in 1949. YNU provides students with a practical education utilizing the wide expertise of its faculty and facilitates engagement with the global community. YNU's strength in the academic research of practical application sciences leads to high-impact publications and contributes to international scientific research and the global society. For more information, please see: https://www.ynu.ac.jp/english/

Yokohama National University

Related Engineering Articles from Brightsurf:

Re-engineering antibodies for COVID-19
Catholic University of America researcher uses 'in silico' analysis to fast-track passive immunity

Next frontier in bacterial engineering
A new technique overcomes a serious hurdle in the field of bacterial design and engineering.

COVID-19 and the role of tissue engineering
Tissue engineering has a unique set of tools and technologies for developing preventive strategies, diagnostics, and treatments that can play an important role during the ongoing COVID-19 pandemic.

Engineering the meniscus
Damage to the meniscus is common, but there remains an unmet need for improved restorative therapies that can overcome poor healing in the avascular regions.

Artificially engineering the intestine
Short bowel syndrome is a debilitating condition with few treatment options, and these treatments have limited efficacy.

Reverse engineering the fireworks of life
An interdisciplinary team of Princeton researchers has successfully reverse engineered the components and sequence of events that lead to microtubule branching.

New method for engineering metabolic pathways
Two approaches provide a faster way to create enzymes and analyze their reactions, leading to the design of more complex molecules.

Engineering for high-speed devices
A research team from the University of Delaware has developed cutting-edge technology for photonics devices that could enable faster communications between phones and computers.

Breakthrough in blood vessel engineering
Growing functional blood vessel networks is no easy task. Previously, other groups have made networks that span millimeters in size.

Next-gen batteries possible with new engineering approach
Dramatically longer-lasting, faster-charging and safer lithium metal batteries may be possible, according to Penn State research, recently published in Nature Energy.

Read More: Engineering News and Engineering Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.