Rowing jellyfish contract to maintain neutral buoyancy  

作　　者：Patricia J.Yang Matthew Lemons David L.Hu 

机构地区：[1]Schools of Mechanical Engineering, Georgia Institute of Technology [2]Schools of Biology, Georgia Institute of Technology

出　　处：《Theoretical & Applied Mechanics Letters》2018年第3期147-152,共6页力学快报（英文版）

基　　金：funding sources Army Research Office 63207-EG

摘　　要：Jellyfish are easily carried by ocean currents, yet most studies on jellyfish focus on the kinematicsin a quiescent fluid. In this experimental and theoretical study, we focus on rowing jellyfish, thosethat partially contract their bells and paddle in a relaxed manner. We film six species of rowingjellyfish in a range of background flow speeds at the Georgia Aquarium. Each species has a uniquecontraction frequency, which is independent of both the body orientation and the backgroundflow speed. Our mathematical model reveals that jellyfish contract to offset their sinking. Thisbehavior is invariant： Despite the background flow conditions, jellyfish contract as if they areoriented upright in a quiescent fluid. Our study suggests that jellyfish operate in open-loop withoutfeedback from their environment.Jellyfish are easily carried by ocean currents, yet most studies on jellyfish focus on the kinematicsin a quiescent fluid. In this experimental and theoretical study, we focus on rowing jellyfish, thosethat partially contract their bells and paddle in a relaxed manner. We film six species of rowingjellyfish in a range of background flow speeds at the Georgia Aquarium. Each species has a uniquecontraction frequency, which is independent of both the body orientation and the backgroundflow speed. Our mathematical model reveals that jellyfish contract to offset their sinking. Thisbehavior is invariant： Despite the background flow conditions, jellyfish contract as if they areoriented upright in a quiescent fluid. Our study suggests that jellyfish operate in open-loop withoutfeedback from their environment.

关 键 词：JELLYFISH THRUST Background flow 

分 类 号：Q66[生物学—生物物理学]