Researchers at Yokohama National University in Japan have developed a unified shock sensor to quickly and accurately dispel harmful shock waves, according to a paper published 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. 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.
In the new study, researchers combined an image 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.
They 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 widely used Ducros sensor is known for its inexpensive efficiency.
Currently, the method is limited to grids of square cells, which is what the imaging software uses. The researchers plan to expand their method to apply to a wide array of differently structured grids. This could be applied to various technologies, including improvements in how a jet dissipates shock.