The initial phase of roll-wave development is investigated by means of spatial linear stability analysis using the St. Venant equations, subject to a pointwise time-varying oscillating disturbance. The predicted spatial growth is compared with both Vedernikov's results and those computed with a fully non-linear model. It is shown that for large values of the channel slope Vedernikov's theory systematically overpredicts the roll waves spatial growth rate, whereas the present analysis yields significant improvements. A modification of Montuori's criterion for the minimum channel length prediction is finally proposed, which agrees with available experimental data independently of the channel slope.
Minimum channel length for roll wave generation
IERVOLINO, Michele;VACCA, Andrea;
2008
Abstract
The initial phase of roll-wave development is investigated by means of spatial linear stability analysis using the St. Venant equations, subject to a pointwise time-varying oscillating disturbance. The predicted spatial growth is compared with both Vedernikov's results and those computed with a fully non-linear model. It is shown that for large values of the channel slope Vedernikov's theory systematically overpredicts the roll waves spatial growth rate, whereas the present analysis yields significant improvements. A modification of Montuori's criterion for the minimum channel length prediction is finally proposed, which agrees with available experimental data independently of the channel slope.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
