Highly nonlinear internal solitary waves and their actions on a cylindrical pile in the northwestern South China Sea

Based on the observation data of a thermistor chain, highly nonlinear internal solitary waves (ISWs) on the continental shelf of the northwestern South China Sea (ISWs) have been observed. The characteristics of the highly nonlinear ISWs with amplitude as large as 45 m are investigated and comparisons are also made between the observation results and existing internal wave theories. Discussion is presented describing how the high-order extended Korteweg-de Vries (EKdV) theory may show better agreement with the observation than the KdV equation. Based on the EKdV theory, Internal wave forces on a cylindrical Pile on the northwestern shelf of SCS are also estimated with the Morison Formula. These results show that ISWs in our study area can cause serious threat to ocean engineering structures and should not be ignored in the design of oil platforms.