Field Particle Image Velocimetry Measurements over Rippled Bedforms during Transitional Wave Forcing

Blake J Landry1, Carlo C Zuniga Zamalloa2, Ryan Mieras2, Joe Calantoni1, Edward F Braithwaite III3, Charles Key1, Callum Gray4, Sean Griffin5 and Alex Sheremet6, (1)U.S. Naval Research Laboratory, Stennis Space Center, MS, United States, (2)National Research Council Research Associateship Program, U.S. Naval Research Laboratory, Stennis Space Center, MS, United States, (3)U.S. Naval Research Laboratory, Ocean Sciences Division, Stennis Space Center, United States, (4)LaVision, Inc., Ypsilanti, MI, United States, (5)Proteus Technologies, LLC, Slidell, LA, United States, (6)University of Florida, Engineering School of Sustainable Infrastructure & Environment (ESSIE), Gainesville, United States
Abstract:
To better elucidate rippled bedform dynamics in the nearshore, high fidelity instrumentation developed for the laboratory was adapted to operate in the field. The newly developed (patent pending) Imaging System for Littoral Environments (ISLE) was deployed in the summer of 2018 within the small harbor near the Hawai’i Undersea Research Laboratory (HURL) located on the southeast corner of the island of Oahu, HI. The area in the vicinity of HURL is characterized by locally-generated wind waves out of the north during the summer months, with occasional far-field, longer period swells. As part of the week-long pilot study, stereo particle image velocimetry (stereo-PIV) of the complex flow field over a rippled sediment bed was acquired along with acoustic Doppler velocimetry (ADV) measurements. The local wave environment was monitored with fast-sampling pressure loggers. Preliminary analysis of stereo-PIV and bedform dynamics is focused on a span of 8.5 hours during which a transition in wave forcing with the arrival of a far-field swell caused reorientation of the local ripple field.