学术报告通知

Lagrangian and multi-scale investigations of turbulent flows

杨越

北京大学工学院

时间：9月30日下午14:00

地点：热能所205会议室

摘要:

The Lagrangian method for the study of turbulence is a classical but challenging approach. We present a series of Lagrangian investigations of turbulent flows with increasing complexities, from the dispersion of tracer particles to the evolution of Lagrangian material surfaces, from Lagrangian kinematics to Lagrangian vortex dynamics, and from the subgrid-scale modeling of inert turbulent mixing to the large-eddy simulation (LES) of turbulent combustion with Lagrangian particle methods. The goal is to develop novel computational and multi-scale methods for quantitative predictions of turbulent mixing and combustion. In particular, we study the non-local geometry of finite-sized Lagrangian structures in homogenous isotropic turbulence and wall-bounded turbulence. The multi-scale geometric analysis is applied on the evolution of Lagrangian fields, to extract Lagrangian structures at different length scales and to characterize their non-local geometry in a space of reduced geometrical parameters. In order to explore the connection and corresponding representations between Lagrangian kinematics and vortex dynamics, we develop a theoretical formulation and numerical methods for computation of the evolution of a vortex-surface field. In the Lagrangian framework, we apply the probability density function (PDF) approach to turbulent combustion with a LES/PDF modeling study of a non-premixed CO/H2 temporally-evolving turbulent planar jet flame. The performance of the hybrid LES/PDF methodology is assessed through detailed a posteriori comparisons with direct numerical simulation of the same flame.

报告人简历:

杨越，2004年浙江大学获热能动力工程学士学位，2007年中国科学院力学所获流体力学专业硕士学位，2011年美国加州理工学院获航空专业博士学位。其博士研究工作为流体湍流与涡动力学发展了原创性的拉格朗日理论框架与多尺度诊断工具，获加州理工学院Richard Bruce Chapman流体力学杰出研究奖。博士后期间获美国普林斯顿大学燃烧能源中心Combustion Energy Research Fellowship资助，于康奈尔大学、桑迪亚国家实验室开展湍流燃烧数值模拟研究工作。2013年加入北京大学工学院，现任力学与工程科学系、湍流与复杂系统国家重点实验室特聘研究员 。