Abstract
In order to examine the water surface features in a laboratory, the sampling moire method was introduced to capture time-dependent two-dimensional profiles. The target flow was a shallow open-channel flow roughened by density packed grass marbles. In order to clarify the spatial and temporal behavior of water surface fluctuations, the frequency wavenumber spectra were calculated. According to the results, the effect of dispersive gravity waves travelling on the surface was greater than non-dispersive waves advected by the turbulence. In addition, the intensity of water surface fluctuation was found to increase with the squared value of the Froude number, which can be estimated from a theoretical consideration.
