Water waves generated by an impulsive bed upthrust of a rectangular block

A theoretical and digital simulation on waves generated by an impulsive bed upthrust of a rectangular block with various ratios of length/width is presented. The two-dimensional fast Fourier transform (FFT) algorithm is used to obtain the water surface profile near the generation region. The three-dimensional pictures were constructed from an array of 256 × 256 pixel by using image processing. Comparison of the present three-dimensional results, with previously published two-dimensional results, indicates that for large length/width ratios, the water surface profile is quite similar at certain locations for a small time after the impulsive bed motion is completed. Generally, the water surface profiles deviate significantly from the two-dimensional results.