Numerical investigations of unsteady critical flow conditions over an obstacle using three models
نویسندگان
چکیده
This paper focuses on the temporal and spatial evolutions of critical flow under unsteady rapidly varied conditions, which is defined based different viewpoints steady gradually conditions in classical fluid mechanics theory. So far, fundamental theory largely unknown for conditions. Taking a Gauss-type weir as an example, this work investigates comprehensively comparatively influences unsteadiness, non-hydrostatic pressure, non-uniform velocity at crest using three models: (i) vertically averaged hydrostatic Shallow Water Equations (SWE); (ii) Serre–Green–Naghdi (SGNE); (iii) vertical velocity-resolved Reynolds-averaged Navier–Stokes (RANSE). The results demonstrate that, all models, points by minimum specific energy, momentum, Froude number equals to unity are generally do not occur crest, except those SWE We found that unsteadiness pressure have significant effects flow, whereas has weak effect. Crest discharge hydrographs revealed SGNE RANSE good modeling options, reliable when shock wave approaches crest. calculated water depth process depth–discharge relationship more accurate than SWE.
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ژورنال
عنوان ژورنال: Physics of Fluids
سال: 2022
ISSN: ['1527-2435', '1089-7666', '1070-6631']
DOI: https://doi.org/10.1063/5.0077585