Dynamics of finite-length compliant cylinders in cross-flow*

Aquatic environments are filled with organisms that sense and interact with flow using finite-length, streamlining structures such as seal vibrissae (ie whiskers) and algae filaments. The compliance of these structures plays a key role in how they interact with surrounding flow and can lead to widely varying dynamics. Prior studies have investigated the advantages and disadvantages of specific systems but further research is required to develop a framework for general understanding of compliant streamers. Experiments investigating finite-length compliant cylinders in turbulent cross-flow were performed in the 12-inch variable pressure water tunnel at the Naval Surface Warfare Center Carderock Division. Cylinders (D = 1 cm, L ~ 10 cm) were fabricated in a range of material compliance and their structural response characterized using Dynamic Mechanical Analysis (DMA). The hydrodynamic behavior of each cylinder was determined from time-resolved measurements of the drag and side force it experienced across Reynolds numbers ranging from  High-speed videography captured the structural response of each cylinder concurrently with force measurements. Details of the flow field are captured for select conditions in separate trials by particle image velocimetry (PIV).