Yokohama claims noise, aero advances

TOKYO (March 20, 2014) — Yokohama Rubber Co. Ltd. (YRC), working with researchers from Japan's aerospace industry, has made advances in the study of turbulence and acoustic waves generated by rolling tires that it claims could lead to breakthroughs in reducing tire-generated noise and improving aerodynamic performance.

Yokohama said the “realization of a simulation of a flow structure enabling precise measurement of acoustic waves” opens up the potential for technological breakthroughs that could lead to reducing pass-by noise generated by tires and improving their  aerodynamic performance at the same time.

YRC researchers made their discoveries while working with a team of researchers led by Professor Kozo Fujii at the Institute of Space and Astronautical Science (ISAS), which is part of Japan Aerospace Exploration Agency (JAXA). Specifically, YRC said they succeeded in the world's first “simulation of near real-scale flow structures (turbulence) around a tire rolling on a road surface and the acoustic waves (noise) generated from these structures.”

Conventional computational methods have limited accuracy in the vicinity of the tire's contact point with the road surface, YRC said. The joint research team succeeded in increasing the accuracy of such computations by using a supercomputer and a high-resolution computational method developed by researchers at ISAS/JAXA for use in space exploration research.

By directly simulating a detailed tire model, the joint research team attained the computations of the air-flow field around a rolling tire at close to actual scale along with its acoustic field, YRC said. As a result, the researchers were able to demonstrate for the first time that the source of noise from tires is not only caused by the turbulence structure around a rolling tire but also from the compressed flow structures in front of a rolling tire caused by the air circulating around it.

This work builds on research Yokohama has undertaken in recent years toward the development of next-generation environmental technologies through the use of various simulations. In 2010, Yokohama Rubber established an aerodynamic simulation technique that enables simulation of air flow around tires under actual use conditions. Using this technique, in December 2012, Yokohama Rubber developed its fin tire design, which reduces aerodynamic drag on a vehicle by controlling the air flow in the wheel well.

YRC said it will continue to support further research in these areas. It did not say how much time or capital was invested thus far in the research.