LABORATORY OBSERVATIONS OF BEDFORMS UNDER DIRECTIONAL IRREGULAR WAVES

Large-scale laboratory tests of the evolution of bedforms in sand beds , under directional irregular waves, carried out at the National Resea rch Council Canada, are described. Preliminary observations indicate t hat the directionality of the waves is not an important factor; bedfor ms remained largely two-dimensional under all but transitional conditi ons. Incident wave height and period, probably combined as a wave orbi tal amplitude near the bed, seems to be the most important factor in d etermining bedform dimensions, followed by the D50 sand size on the be d. Sand gradation may be unimportant.