Tsunami Induced Turbulent Coherent Structures Tsunami Induced TCS Nearbed TCS Shallow horizontal TCS Near-surface breaking TCS Harbors and Ports Pick up and Liquefaction Scour z y x Diane Foster (UNH), Pat Lynett (USC), and Tom Hsu (Udel) Sponsor: NSF CMMI

Tsunami Induced Turbulent Coherent Structures Nearbed TCS Pick up and Liquefaction Scour With significant intellectual contributions from Donya Frank and Meagan Wengrove z y x

Observations NEESR – Large Wave Flume – O. H. Hinsdale Wave Research Lab Wave Conditions – Long Waves – Short Waves & Long Waves – Short Waves

Observations BL measurements – u, v, w – 1 mm range bins over 3 cm – 100 Hz Bed Roughnesses – Flat – Rippled – Rough

Observations BL meaurements – u, v, w – 1 mm range bins – 100 Hz Bed Roughnesses – Flat – Rippled – Rough

Single solitary over a flat smooth bed u (m/s) w (m/s)

Single solitary over a flat smooth bed u (m/s) w (m/s)

Reynolds Stress Estimate u

u 

Rough Bed Flat Rippled Rough

Smart Sediment Grains Dimensions: – 2.5 x 1.5 x 1.4 cm Components: – 2 triaxial accelerometers, memory card, battery and wireless transmitter. Enclosure: – 4.4 cm Delrin plastic sphere – Combined specific gravity of 1.3

Overview of Test Results Preliminary tests – Low noise floor: 0.3 m/s 2 – Accurate reproduction of oscillations with reference accelerometer Large-scale wave tank tests – Height=0.20m, Period=3s – Incipient motion at Shields of and Sleath of 0.12 – Results indicated plug flow sediment transport regime

X-Force Balance yields:where: Incipient Motion bb T p > ~ 0.37 Sleath (1999)  > 0.04~0.08 incipient motion  > 0.8sheet flow S > 0.29 plug flow

X-Force Balance yields:where: Incipient Motion bb T p > ~ ? Sleath (1999)  > 0.04~0.08 incipient motion  > 0.8sheet flow S > 0.1 plug flow

Thank you Boundary Layer observations over fixed beds Particle accelerations of incipient motion and rolling grains