A laboratory benchmark test for tsunami inundation through an urban waterfront including free surface elevation, velocity, and specific momentum flux is presented and compared with a numerical model (COULWAVE). The physical model was a 1:50 scale idealization of the town Seaside, Oregon, designed to observe the complex tsunami flow around the macro-roughness such as buildings idealized as impermeable, rectangular blocks. Free surface elevation and velocity time series were measured and analyzed at 31 points along 4 transects. Optical measurements of the leading bore front were used in conjunction with the in-situ velocity and free surface measurements to estimate the time-dependent specific momentum flux at each location. The maximum free surface elevation and specific momentum flux sharply decreased from the shoreline to the landward measurement locations, while the cross-shore velocity slowly decreased linearly. The
experimental results show that the maximum specific momentum flux is overestimated by 60 to 260%, if it is calculated using the each maximum values of the free surface elevation and cross-shore velocity. Comparisons show that the numerical model is in good agreement with the physical model at most locations when tuned to a friction factor of 0.005. When the friction factor decreased by a factor of 10 (from 0.01 to 0.001), the average maximum free surface elevation increased 15%, and the average cross-shore velocity and specific momentum flux increased 95 and 208%, respectively. This highlights the importance of comparing velocity in the validation and verification process of numerical models of tsunami inundation.

Authors: 
Park, H., D. Cox, P. Lynett, D. Wiebe, & S. Shin
Short Description: 
This project presents a model study of tsunami flow over and around macro-roughness in the idealized physicalmodel of Seaside, Oregon, and provides a new data set of free surface elevation, velocity, and momentum to be used as a benchmark test.
Product Number: 
ORESU-R-13-014
Entry Date: 
Monday, May 12, 2014
Length: 
13 pp.
Size and Format: 
8 1/2 x 11, online
Source (Journal Article): 
Coastal Engineering
DOI Number (Journal Article): 
10.1016/j.coastaleng.2013.04.002
Year of Publication: 
2013