On the Shoaling of Solitary Waves in the Presence of Short Random Waves

Monday, 15 December 2014
Miao Tian1, Alexandru Sheremet1, James Michael Kaihatu2 and Gangfeng Ma3, (1)University of Florida, Engineering School of Sustainable Infrastructure & Environment, Gainesville, FL, United States, (2)Texas A&M University, College Station, TX, United States, (3)Old Dominion University, Department of Civil and Environmental Engineering, Norfolk, VA, United States
Overhead video from a small number of laboratory experiments conducted by Kaihatu et al. (2012) at the Tsunami Wave Basin at Oregon State University shows that the breaking point of a shoaling solitary wave shifts to deeper water if random waves are present. The analysis of the laboratory data collected confirms that solitary waves indeed tend to break earlier in the presence of random waves-fields, and suggests that the effect is the result of radiation-stresses induced by the random wave fields. A theoretical approach based on the forced KdV equation is shown to successfully predict the shoaling process of the solitary wave. A statistical ensemble simulated using a state of the art non-hydrostatic model (NHWAVE) is used to test the significance of the process. The results of this study point to a potentially significant oceanographic process that has so far been ignored, and suggest that systematic research into the interaction between tsunami waves and the swell background could increase the accuracy of tsunami forecasting.