The depth inversion problem in shallow water

Proc. 3rd Intl. Intl. Sympos. on Ocean Wave Measurement and Analysis (WAVES97, Virginia Beach, VA, USA, November 1997) (eds. B. Edge, &J.M. Hemsley), 701-715, ASCE Publication.

Stephan T. Grilli

Distinguished Professor
Department of Ocean Eng.
University of Rhode Island
Narragansett, RI 02882, USA

Abstract :  

Two Depth Inversion Algorithms (DIAs) were developed and validated using on results of computations for the shoaling of periodic waves over mild slopes, in a two-dimensional numerical wave tank, based on fully nonlinear potential flow theory. The first algorithm, DIA1, uses sets of values of wave celerity c, height H, and spatial wavelengths Lc and Lt, simultaneously measured at a number of locations xi (i=1,...,N) in the direction of wave propagation (e.g., using remote sensing techniques), to predict the depth variation h(xi). The second algorithm, DIA2, uses spatial wave asymmetry s2/s1 calculated from wave phase, instead of H. Results indicate that state-of-the-art depth inversion methods based on the linear dispersion relation may lead to large errors (50-70%) for the depth prediction in very shallow water, whereas the present methods are 3-10 times more accurate.

Keywords :

Wave propagation, nonlinear wave models, shallow water, numerical methods, inverse modeling, depth prediction, coastal engineering.

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