Open channel flow past a bottom obstruction

A new nonlinear integral-equation model is derived in terms of hodograph variables for free-surface flow past an arbitrary bottom obstruction. A numerical method, carefully chosen to solve the resulting nonlinear algebraic equations and a simple, yet effective radiation condition have led to some very encouraging results. In this paper, results are presented for a semi-circular obstruction and are compared with those of Forbes and Schwartz [1]. It is shown that the wave resistance calculated from our nonlinear model exhibits a good agreement with that predicted by the linear model for a large range of Froude numbers for a small disturbance. The small-Froude-number non-uniformity associated with the linear model is also discussed.