• [2013-02-27]

  Professor Shiyi Chen’s team made progress in the research of compressible turbulence

Recently, a research team in the College of Engineering has made important progress in the study of compressible turbulence, which has been published in Physical Review Letters (Acceleration of Passive Tracers in Compressible Turbulent Flow, Phys.Rev.Lett.110, 064503, 2013). The team is led by Professor Shiyi Chen in the State Key Laboratory for Turbulence and Complex Systems (SKLTCS) and Professor Xiantu He in the Center for Applied Physics and Technology (CAPT). Other contributors include Dr. Yantao Yang, Dr. Jianchun Wang, Prof. Yipeng Shi, and Prof. Zuoli Xiao.

Compressible turbulence has proved to be one of the key problems in many natural phenomena and engineering flows, including star formation from interstellar gas, inertial confinement fusion, and hypersonic aircraft. Based on their previous study (Phys.Rev.Lett. 108, 214505, 2012), Prof. Chen’s group continued to explore the compressible turbulence from the Lagrangian point of view, which is especially crucial for understanding turbulent dispersion and mixing.

They found that two different types of flow structure, i.e. shocklets and vortices, induce distinct dynamic behaviors of passive tracers. Therefore, the time dynamics of passive tracers exhibits two separated time scales. Shocklets decorrelate the acceleration of passive tracer in a very short time period, which is totally different from the effect of intense vortices as in the incompressible turbulence. In the smooth region of flow domain, the Probability Density Function (PDF) of acceleration obeys Log-normal distribution. While in the strong compression region a power law emerges in the acceleration PDF, which can be directly related to the local compression. Large curvature appears on the tracer trajectory near shocklets. All these results could help develop more advanced model for compressible turbulence.

This study is supported by the National Natural Science Foundation of China, the National Science and Technology Ministry as a subproject of 973 program, China Postdoc Foundation, and CAPT of Peking University.

Different behaviors of passive tracers near shocklets and vortices.

 Different PDF distribution of acceleration in different flow region.