<abstract xmlns="http://www.w3.org/1999/xhtml"><p>The present work investigates the effect of the flow profile induced by an inlet condition on the roll-wave evolution in turbulent clear-water flows. The study employs theoretical and numerical analyses. Firstly, the influence of the inlet condition on the spatial evolution of a single perturbation in a hypercritical flow is examined through the expansion near a wavefront analysis. The results show that an accelerated unperturbed profile reduces the disturbance spatial growth. A decelerated profile causes an increase. The effect of the flow profile on the spatial evolution of roll-wave trains is then numerically investigated solving the Saint Venant equations with a second-order Runge-Kutta Total Variation Diminishing (TVD) Finite Volume scheme. The numerical simulations comply with the analytical results for the initial and transition phases of the roll-wave development. The unperturbed profile influences even the roll-waves statistical characteristics in the final stage, with a more evident effect in case of accelerated profiles. The influence of the flow profile should be therefore accounted for in the formulation of predictive criteria for roll-waves appearance based on the estimation of the disturbance spatial growth rate.</p></abstract>

The present work investigates the effect of the flow profile induced by an inlet condition on the roll-wave evolution in turbulent clear-water flows. The study employs theoretical and numerical analyses. Firstly, the influence of the inlet condition on the spatial evolution of a single perturbation in a hypercritical flow is examined through the expansion near a wavefront analysis. The results show that an accelerated unperturbed profile reduces the disturbance spatial growth. A decelerated profile causes an increase. The effect of the flow profile on the spatial evolution of roll-wave trains is then numerically investigated solving the Saint Venant equations with a second-order Runge-Kutta Total Variation Diminishing (TVD) Finite Volume scheme. The numerical simulations comply with the analytical results for the initial and transition phases of the roll-wave development. The unperturbed profile influences even the roll-waves statistical characteristics in the final stage, with a more evident effect in case of accelerated profiles. The influence of the flow profile should be therefore accounted for in the formulation of predictive criteria for roll-waves appearance based on the estimation of the disturbance spatial growth rate.

Inlet effects on roll-wave development in shallow turbulent open-channel flows

Dipartimento di Ingegneria e Architettura, Università di Trieste, Piazzale Europa 1, 34127 Trieste, Italy.

Dipartimento di Ingegneria Civile e Meccanica, Università di Cassino e del Lazio Meridionale, Via Di Biasio 43, 03043 Cassino (FR), Italy.

Dipartimento di Ingegneria Civile, Design, Edilizia ed Ambiente, Seconda Università di Napoli, Via Roma 29, 81031 Aversa (CE), Italy.

Journal of Hydrology and Hydromechanics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Inlet effects on roll-wave development in shallow turbulent open-channel flows"}

The present work investigates the effect of the flow profile induced by an inlet condition on the roll-wave evolution in turbulent clear-water flows. The study...

Inlet effects on roll-wave development in shallow turbulent open-channel flows

Published Online: Jan 26, 2016

Page range: 45 - 55

Received: Jun 19, 2015

Accepted: Oct 16, 2015

DOI: https://doi.org/10.1515/johh-2016-0003

Keywords
Open-channel flows, Roll-waves, Hypercritial flows, Numerical simulation

© 2016 Francesca Campomaggiore et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Inlet effects on roll-wave development in shallow turbulent open-channel flows

Published Online: Jan 26, 2016

Page range: 45 - 55

Received: Jun 19, 2015

Accepted: Oct 16, 2015

DOI: https://doi.org/10.1515/johh-2016-0003

KeywordsOpen-channel flows, Roll-waves, Hypercritial flows, Numerical simulation

© 2016 Francesca Campomaggiore et al., published by De Gruyter Open

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Open-channel flows, Roll-waves, Hypercritial flows, Numerical simulation