Long waves associated with bichromatic waves

A numerical model of low frequency waves is presented. The model is based o n that of Roelvink (1993), but the numerical techniques used in the solutio n are based on the so-called Weighted- Average Flux (WAF) method with Time- Operator- Splitting JOS) used for the treatment of the source terms. This m ethod allows a small number of computational points to be used, and is part icularly efficient in modeling wave setup. The short wave (or primary wave) energy equation is solved with a traditional Lax-Wendroff technique. A non linear wave theory is introduced. The model described in this paper is foun d to be satisfactory in modeling low frequency waves associated with incide nt bichromatic waves.