Numerical Simulation Of Two-dimensional Waves Based On Conditional Simulation Method

Conditional simulation is a concept that has emerged in geostatistics in recent years.Its core concept is to reproduce the data field mathematically based on the statistical characteristics of a particular data field(including mathematical expectations,probability distribution forms,covariance functions,mutation functions,etc.).This reproduced field has the same statistical characteristics as the original data field.When performing wave simulation and its action on structures in laboratory,a special wave(such as focusing wave)is sometimes considered to the wave action on structures.Generally,the special wave belong to an irregular wave series.Therefore,it is necessary to generate a random wave train that meets a specific spectrum and contains a special short wave train.This often requires a large number of wave simulations and wave-by-wave analysis from many random wave trains to find waves because of the randomness when traditional random wave superposition method is used for the wave simulation.This is time-consuming and laborious.However,the conditional simulation method can be applied to this requirement.The special wave can be embedded into an irregular wave series and the needed wave trains can be quickly simulated.Therefore,based on the conditional simulation method,the irregular wave simulation approach is established to simulate the needed special waves.This will promote the efficiency and research level for the irregular wave action on structures.In this paper,based on Borgman's conditional simulation wave theory,a numerical wave simulation method was established in a two-dimensional case.By adding white noise,the numerical instability problem caused by the ill-conditioned matrix in the calculation was solved.It can be implemented in a random wave train belonging to a specific spectrum,and embedded in a specific wave train at any reasonable time point.The new random wave train still satisfied the specific spectrum.With regular wave and focused wave as the embedded wave train,the effects of the length,period,wave height and embedded point of the embedded wave on the simulation are studied.The numerical simulated results show that embedded time point,the embedded wave height and length have no evident effect on the simulated waves.But if the embedded wave height is comparably big,the maximum wave height of the simulated waves will be bigger.However,the embedded wave period and the unconditionally simulated wave period should be compatible.It is recommended that the ratio of the effective period of the embedded wave train to the effective period of the initial wave train be controlled between 0.75 and 1.25.On this basis,the Fluent software is used to establish a numerical wave tank,and the wave making experiment is performed on the target wave train.The wave series with embedded waves can be generated in numerical fluent.In this paper,a method is established to simulate a specific wave in an irregular wave series and associated software is programmed.It provides a new approach to physically and numerically simulate characteristic wave and its action on structures.