Hydrokinetic oscillators for ocean energy sources

The Space and Naval Warfare Systems Center Pacific (SSC Pacific) is currently researching the use of hydrokinetic oscillators to generate power for remote ocean systems. These cylinder oscillators would harness the same Flow Induced Vibration (FIV) mechanisms that often lead to annoying perturbations, flow noise and sometimes structural failures in offshore structures, cables, and heat exchanger tubes. A Yr 1 hydrokinetic oscillator was developed to demonstrate undersea energy harvesting in 1 m/s flows with flow induced vibrations (FIV) imparted on a cantilevered cylinder (200 mm × 12.7 mm dia). The program goal is to combine a compact cylinder oscillator with an SSC Pacific Kinetic Energy Harvester (KEH) that operates at 10 - 15 Hz and which could output 200 to 700 mW power if exposed to 1 - 2 g-rms vibrations. Midterm Yr 1 tests were conducted on a 12.7 mm diameter cylinder and KEH mockup in 0.6 m/s flow and resulted in 8 Hz oscillation frequencies with 1 - 2 g accelerations. Further testing with other cylinder configurations and flow speeds will be conducted in Fall 2011 at the Scripps Institute of Oceanography Stratified Flow Channel in La Jolla, CA.