A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 1998

The 2-D numerical model developed by Rattanapitikon(1991) is used to simulate the dam break wave propagation over composite planes and reflection of surge from downstream end. The governing equations namely the continuity equation, the x and y momentum equations are solved numerically using the two step predictor-corrector method in conjunction with the asymmetric finite difference scheme. Five experiments of dam break are carried out considering different initial reservoir head, different width of downstream opening and different bed slope the composite planes. The dam break propagation spreads over the composite planes in a two dimensional way over a dry bed . According to the comparison of the observed and computed results the present model can simulate the 2-D dam break wave very well only along the centreline except near the dam break section where the 3-D effect of the outflow through the dam break section is significant. The stations located left and right of the centerline, the computed and observed results also agree very well. Sensitivity analysis of the present model is carried out. The Manning roughness coefficient has a significant effect on the computed water depth hydrographs and the propagation of wave front. The small depth h1 and limiting depth of wave front dr have a small effect on the path of wave front and but has insignific~nt effect on the pattern of wave front propagation. The use of predictor corrector procedure with the asymmetric finite difference scheme has no significant effect on improvement of the wave front propagation but significant improvement on the computed water depth hydro graphs.