2013年12月9日（周一）下午3:00，物理系seminar：

报告题目： Secrets of swimming in sand 报告人：丁阳 Aerospace and Mechanical Engineering, University of Southern California，USA 报告时间： 2013-12-9 15:00 报告地点：理科楼三楼报告厅摘要： Locomotion within granular media like sand, soil and debris that display both solid and fluid-like behavior is challenging and not well understood. Here I summarize my modeling efforts to understand the swimming of the sandfish lizard in sand. High speed x-ray imaging showed that the 10 cm-long sandfish swims at 2 body-lengths/sec within sand by propagating an undulatory traveling wave down the body. To predict the sandfish swimming speed in sand, we developed an empirical resistive force model by measuring drag force on a small cylinder oriented at different angles relative to the displacement direction and summing these forces over the animal movement profile. The model correctly predicts the animal's wave efficiency (ratio of forward speed to wave speed) as approximately 0.5. The model also explains the muscle activation pattern observed on sandfish and solved a long-standing puzzle of undulatory swimmers. The empirical model agrees with a more detailed numerical simulation: a multi-segment model of the sandfish coupled to a multi-particle discrete element method (DEM) simulation of the granular medium. 个人简介：丁阳，本科毕业于中国科技大学，2011年在佐治亚理工学院(Georgia Tech) 获得物理博士学位，现于美国南加州大学(University of Southern California)做博士后。丁阳的研究方向为动物运动和复杂物质。