High-angle formulation for the nonlinear progressive-wave equation model

The nonlinear progressive-wave equation (NPE) model has been reformulated f or wider propagation angle accuracy. The wide angle NPE results from range- integrating the second order time domain nonlinear wave equation rather tha n reducing it to a first order equation in time as in the original NPE. The numerical implementation of the second order NPE retains two time levels r ather than one. The resulting model is refered to as NPE2. Benchmark tests reveal RMS errors in the model are reduced by nearly a factor of 10 for mod erately high propagation angles as compared to errors in similar tests of t he first order NPE. (C)2000 Elsevier Science B.V. All rights reserved.