Pages 205-210
For model experiments of a ship model with forward velocity, it is desirable that directional irregular waves are stationary in space. By making use of wave measurement and numerical calculation, this paper examines homogeneousness of directional irregular waves generated by a signal calculated with a conventional double-summation method in a model basin where side-wall reflections are positively utilised. The measured results indicate that variance of water surface is not stationary in space. In theory, such non-homogeneousness can be caused by the double-summation method for the wave-making signal or side-wall reflections. The numerical calculation of a summation of many cosine waves realised similar non-homogeneousness that observed in the wave measurement. This numerical result indicates that the non-homogeneousness is mainly due to the double-summation method for the wave-making signal but not mainly due to the side-wall reflections.
