A spatial linear stability analysis of the one-dimensional St. Venant flow model, accounting for the dis-persive effects, is carried out in the present paper. The theoretical investigation allows to discuss about the influence of channel length on roll-waves occurrence. In order to provide a rigorous justification for se-lecting the spatial stability theory, a preliminary proof of the convective nature of the flow instability is fur-thermore performed. The results of the spatial analysis show a non-negligible influence of the disturbance frequency on the perturbation spatial growth rate. As a consequence the semi-empirical criteria commonly employed for predicting roll-waves occurrence, which do not take into account the frequency effects, may lead to overestimate the minimum channel length above which the phenomenon is not perceivable.
Dispersive effects on linear instability of the Saint Venant flow model.
DI CRISTO, Cristiana;
2004-01-01
Abstract
A spatial linear stability analysis of the one-dimensional St. Venant flow model, accounting for the dis-persive effects, is carried out in the present paper. The theoretical investigation allows to discuss about the influence of channel length on roll-waves occurrence. In order to provide a rigorous justification for se-lecting the spatial stability theory, a preliminary proof of the convective nature of the flow instability is fur-thermore performed. The results of the spatial analysis show a non-negligible influence of the disturbance frequency on the perturbation spatial growth rate. As a consequence the semi-empirical criteria commonly employed for predicting roll-waves occurrence, which do not take into account the frequency effects, may lead to overestimate the minimum channel length above which the phenomenon is not perceivable.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
