A simple estimation of the force exerted by internal solitons on cylindrical piles

Internal solitons can bring about strong force on the oil drilling platform and pipeline at sea, which causes severe threat to the ocean engineering. Cai et al. (2003) introduced Morison's empirical formula, modal separation method and regression analyses to estimate the forces exerted by internal soliton on cylindrical piles. However, this method is very complicated and it requires some observational current data which are generally very difficult to obtain synchronically. In this paper, it is shown that the force by the first mode internal wave dominates most part of the global force, thus a new simple estimation method of the force based on only the first mode internal wave is put forward without some complicated steps and observational current data in the old method. The force can be estimated by the local vertical observational temperature, salinity data and amplitude of internal soliton.