Hydraulic condition for undular-jump formations

Ohtsu, Iwao; Yasuda, Youichi; Gotoh, Hiroshi

doi:10.1080/00221680109499821

Cited by 69 publications

(30 citation statements)

References 8 publications

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“…The cross-waves propagated behind the first wave crest, they were reflected on the opposite sidewall and they gave a lozenge pattern to the free-surface. A similar cross-wave pattern was observed in stationary undular hydraulic jumps [40,41] and undular surges [22,23].…”

Section: Basic Flow Patternssupporting

confidence: 50%

Experimental study of a positive surge. Part 1: basic flow patterns and wave attenuation

Gualtieri

Chanson

2011

Environ Fluid Mech

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A positive surge results from a sudden change in flow that increases the depth. It is the unsteady flow analogy of the stationary hydraulic jump and a geophysical application is the tidal bore. Positive surges are commonly studied using the method of characteristics and the Saint-Venant equations. The paper presents the results from new experimental investigations conducted in a large rectangular channel. Detailed unsteady velocity measurements were performed with a high temporal resolution using acoustic Doppler velocimetry and non-intrusive free-surface measurement devices. Several experiments were conducted with the same initial discharge (Q=0.060 m³/s) and 6 different gate openings after closure resulting in both non-breaking undular and breaking bores. The analysis of undular surges revealed wave amplitude attenuation with increasing distance of surge propagation were in agreement with Ippen and Kulin theory. Also, undular wave period and wave length data were relatively close to the values predicted by the wave dispersion theory for gravity waves in intermediate water depths.

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Section: Basic Flow Patternssupporting

confidence: 50%

Experimental study of a positive surge. Part 1: basic flow patterns and wave attenuation

Gualtieri

Chanson

2011

Environ Fluid Mech

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“…However a non-breaking undular jump is observed at low Froude numbers. The transition from a stationary undular jump into a jump with a marked breaking roller takes place with the progressive apparition of characteristic three-dimensional flow features with increasing Froude numbers, including cross-waves and cockscomb roller (Montes 1995, Chanson 1995, Ohtsu et al 2001. A hydraulic jump with a fully-developed breaking roller is observed only for Froude numbers greater than 2 to 4 (Ryabenko 1990, Chanson 2009).…”

Section: How Can Better Flow Analogies Help?mentioning

confidence: 99%

Are breaking waves, bores, surges and jumps the same flow?

Lubin

Chanson

2016

Environ Fluid Mech

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The flow structure in the aerated region of the roller generated by breaking waves remains a great challenge to study, with large quantities of entrained air and turbulence interactions making it very difficult to investigate in details. A number of analogies were proposed between breaking waves in deep or shallow water, tidal bores and hydraulic jumps. Many numerical models used to simulate waves in the surf zone do not implicitly simulate the breaking process of the waves, but are required to parameterise the wave-breaking effects, thus relying on experimental data. Analogies are also assumed to quantify the roller dynamics and the energy dissipation. The scope of this paper is to review the different analogies proposed in the literature and to discuss current practices. A thorough survey is offered and a discussion is developed an aimed at improving the use of possible breaking proxies. The most recent data are revisited and scrutinised for the use of most advanced numerical models to educe the surf zone hydrodynamics. In particular, the roller dynamics and geometrical characteristics are discussed. An open discussion is proposed to explore the actual practices and propose perspectives based on the most appropriate analogy, namely the tidal bore.

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“…Este tren de ondas puede tener una extensión considerable, y reemplaza al vórtice del resalto hidráulico clásico (Figura 1b). El fenómeno del resalto hidráulico ondulatorio es complejo y ha recibido considerables esfuerzos para caracterizarlo mediante modelos físicos (Ryabenko, 1990;Chanson, 1993Chanson, , 1995Chanson, , 1996Chanson, , 2000Chanson, , 2009Chanson y Montes, 1995;Reinauer y Hager, 1995;Ohtsu et al, 2001Ohtsu et al, , 2003Gotoh, et al, 2005). La estructura del resalto ondulatorio es bidimensional para valores F o <1.2 (Reinauer y Hager, 1995).…”

Section: Introductionunclassified

“…No obstante, Ryabenko (1990) encontró mediante medidas en modelo físico que el resalto ondulatorio es muy sensible a las condiciones del flujo de aproximación, en concreto, a la existencia de una distribución no hidrostática de la presión en el mismo. Reinauer y Hager (1995) determinaron la misma sensibilidad del resalto a las condiciones de aproximación si el calado de aproximación es pequeño y provoca efectos de escala, mientras que Ohtsu et al (2001) encontraron que el desarrollo de la capa límite en la sección de aproximación es igualmente importante. La caracterización matemática del resalto ondulatorio es por tanto compleja, debido a la existencia de un tren de ondas que invalida la hipótesis de presión hidrostática usada en modelos de flujo gradualmente variado, además de a otros fenómenos como la existencia de ondas de choque y la gran dependencia de las condiciones de flujo de aproximación.…”

Section: Introductionunclassified

Resalto Hidráulico Ondulatorio

Castro-Orgaz¹,

Roldán²,

Dolz

2015

ing.agua

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ResumenLa transición de régimen supercrítico a régimen subcrítico cuando el número de Froude F o aguas arriba está próximo a la unidad da lugar a un tren de ondas estacionario llamado resalto hidráulico ondulatorio. La caracterización del resalto ondulatorio es muy compleja, debido a que el tren de ondas invalida la hipótesis de presión hidrostática usada en modelos de flujo gradualmente variado, y a otros fenómenos como las ondas de choque del flujo supercrítico. El objetivo de este trabajo es presentar un modelo para el resalto hidráulico ondulatorio obtenido de las ecuaciones de Reynolds para flujo turbulento, asumiendo que el número de Reynolds R es elevado. Se presentan soluciones analíticas sencillas para mostrar las características físicas de la teoría, así como un modelo numérico para la integración de las ecuaciones completas. El límite de aplicación de la teoría se discute en relación a la rotura de onda y formación de vórtices. La validez del modelo matemático es revisada de forma crítica usando datos en modelo físico, para resaltar aspectos en los que es necesaria más investigación.. Palabras clave

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Hydraulic condition for undular-jump formations

Cited by 69 publications

References 8 publications

Experimental study of a positive surge. Part 1: basic flow patterns and wave attenuation

Experimental study of a positive surge. Part 1: basic flow patterns and wave attenuation

Are breaking waves, bores, surges and jumps the same flow?

Resalto Hidráulico Ondulatorio

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