By comparing model results from tests of steady and oscillatory flows over a submerged bar (of interest for both riverine and marine environments), we highlight similarities and differences between a state-of-the-art Boussinesq model and a recently developed non-hydrostatic, quasi-three-dimensional (3D) model. To make the comparison as clean as possible, the complexities due to breaking-induced turbulence are avoided by suitably tuning the flow strength. Although the main flow features are similarly described by the two models, the non-hydrostatic model predicts the occurrence of extra, small-scale stationary oscillations on top of a submerged obstacle in the case of a steady current. This is attributed to a pattern of alternating upward and downward vertical velocity over the sill top, presumably due to rapidly converging flows as they climb over the submerged obstacle. The non-hydrostatic model overall allows for a more complete representation of flow dynamics in the vertical direction, with respect to the Boussinesq-type solver. This becomes necessary when tackling fundamental and applicative problems characterized by intense vertical flows (e.g., interactions of fluids with structures).

From Boussinesq-Type to Quasi-3D Models: A Comparative Analysis / Melito, Lorenzo; Antuono, Matteo; Brocchini, Maurizio. - In: JOURNAL OF HYDRAULIC ENGINEERING. - ISSN 0733-9429. - ELETTRONICO. - 149:8(2023). [10.1061/JHEND8.HYENG-13508]

From Boussinesq-Type to Quasi-3D Models: A Comparative Analysis

Melito, Lorenzo
Primo
Conceptualization
;
Brocchini, Maurizio
Ultimo
Conceptualization
2023-01-01

Abstract

By comparing model results from tests of steady and oscillatory flows over a submerged bar (of interest for both riverine and marine environments), we highlight similarities and differences between a state-of-the-art Boussinesq model and a recently developed non-hydrostatic, quasi-three-dimensional (3D) model. To make the comparison as clean as possible, the complexities due to breaking-induced turbulence are avoided by suitably tuning the flow strength. Although the main flow features are similarly described by the two models, the non-hydrostatic model predicts the occurrence of extra, small-scale stationary oscillations on top of a submerged obstacle in the case of a steady current. This is attributed to a pattern of alternating upward and downward vertical velocity over the sill top, presumably due to rapidly converging flows as they climb over the submerged obstacle. The non-hydrostatic model overall allows for a more complete representation of flow dynamics in the vertical direction, with respect to the Boussinesq-type solver. This becomes necessary when tackling fundamental and applicative problems characterized by intense vertical flows (e.g., interactions of fluids with structures).
2023
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11566/316513
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