ANALYSIS OF FALSE WAVES IN NUMERICAL SEA SIMULATIONS

It is common practice to consider the random sea waves as a succession of discrete waves characterized by individual amplitudes and periods. The zero-up-crossing criterion for discretizing waves, as well as oth er criteria proposed by different authors, has been found to isolate s ome discrete waves that do not correspond to physical waves. These fal se waves alter the wave statistics of random sea waves. A new orbital criterion is proposed to avoid this problem. The orbital criterion has been shown to be consistent and robust with respect to the zero-up-cr ossing criterion. Furthermore, the new criterion produces a distributi on of wave heights in better agreement with the Rayleigh distribution. The mean period of the discrete waves corresponding to the orbital cr iterion is proved to be T01, while the mean period of the zero-up-cros sing waves is T02. A formula relating the Longuet-Higgins spectral ban dwidth nu with the relative number of false waves is given.