2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/143147We describe the physical hypotheses underlying the derivation of an approximate model of water waves. For unidirectional surface shallow water waves moving over an irrotational flow as well as over a non-zero vorticity flow, we derive the Camassa-Holm equation by an interplay of variational methods and small-parameter expansions.14 pagesMathematical Physics35Q58, 76B15, 70G75Variational derivation of the Camassa-Holm shallow water equation with non-zero vorticitytext