报告题目：Towards Uncovering the Interaction between Turbulence and Structures
报 告 人：Prof. Chamorro 美国伊利诺伊大学香槟分校
摘 要：The interaction between turbulence and structures involves dynamics characterized by multiscale, nonlinear processes. Despite its complexity, close inspection on selected problems reveal common and distinctive effects of turbulence. Here, I will briefly illustrate our efforts in boundary layer flows, Lagrangian dynamics in convection, and others. Then, I will take a closer look in (very) different cases of flow-structure interaction, namely the rotation of rigid bodies, the motion of flexible plates as well as the power output of wind turbines and wind farms. The underlying dynamics of these structures is fundamentally described from basic concepts. Laboratory experiments using hotwire anemometry, particle tracking velocimetry (PTV) and particle image velocimetry (PIV) combined with theory are used to unravel and explain the characteristic power-law decays of the spectra of rotation and oscillation of plates as well as the power output of wind turbines. I will show that the energy-containing eddies and the inertial subrange of the incoming velocity spectrum strongly modulate the unsteady motions of structures and turbine power. A derived tuning-free model based on a transfer function and turbulence spectrum, supported with experiments, reveals common spectral trends across the cases studied.
报告人简介：Dr. Chamorro is an assistant professor in the department of Mechanical Science and Engineering in the University of Illinois at Urbana-Champaign. He is affiliated to the departments of Aerospace Engineering, and Civil and Environmental Engineering. His research interests include experimental fluid mechanics, turbulence, wind energy, marine and hydrokinetic energies, flow-structure interaction, particle transport, and boundary layer processes. He has published 56 peer-reviewed articles in leading journals and is serving as Associate Editor of the Journal of Energy Engineering, and as Academic Editor and member of the Editorial Board of the journal Energies. He leads the Renewable Energy and Turbulent Environment group, where developed a versatile experimental approach that combines state-of-the-art techniques, including 2D/3D PIV, computer vision, and 3D particle tracking velocimetry.
报告题目：Revisiting of paleoclimate recording δ18O as scalar turbulence
报告人：黄永祥副教授 State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, People’s Republic of China
摘要：Multifractality feature has been identified in the historical recording of δ18O (18O/16O ratios), which has been considered as a climate proxy of temperature. However, two facts are still unclear. One is the Hurst number, and the other one is the multifractal strength. In this work, we revisit a high-resolution paleoclimate historical recording of δ18O obtained from the North Greenland Ice-Core Project (NGRIP) with a time resolution 50-year. The multifractality property of this data is then concerned by extremal-point-density analysis and Hilbert-Huang transform. A Hurst number H = 1/3 and intermittency parameter μ = 0.64 are determined. It leads new insight to the paleoclimate dynamics and bring new challenge to the climate model simulation that a physical constrain reported in this paper must be taken into account.
曾获2013年欧洲地球科学联盟地球科学中非线性过程部杰出青年科学奖，目前已发表Journal of Fluid Mechanics 等SCI收录文章40余篇，并由剑桥大学出版社出版英文专著一部。