Experiments on air entrainment produced by a circular free falling jet

Torre, Reyna Guadalupe Ramírez de la; Kuchta, Miroslav; Jensen, Atle

doi:10.1016/j.ijmultiphaseflow.2020.103424

Cited by 13 publications

(5 citation statements)

References 23 publications

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“…The conditions at which air entrainment begins are related to the behavior and shape of the meniscus. The analysis of publications referring to the subject of this study [9,[11][12][13][14][15][16][17][18][19] shows that the process of jet interaction with the liquid surface is complex. At the same time, the theoretical approaches to its description are underdeveloped.…”

Section: Introductionmentioning

confidence: 90%

Evaluating the critical velocity of air entrainment by plunging water jets

2023

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It has been found that air entrainment occurs when the average jet velocity at the plunging point reaches a certain value. This velocity is called the critical velocity of air entrainment. The analysis of studies in this field shows that the process of jet interaction with the liquid surface is complex, while the theoretical approaches to its description are insufficient. The conditions at which air entrainment begins are related to the behavior and shape of the meniscus. The mechanism of meniscus formation is based on the complicated kinematic structure of motion in the vicinity of the point of interaction between the jet and the liquid in the quiescent state. Experiments and observations show that the meniscus behavior is closely related to the initial conditions of air entrainment. Calculating the critical velocity of air entrainment Ue, analysis of the meniscus shape, and use of the limit equilibrium condition were used to derive a new criterion relationship for the air entrainment conditions of turbulent jets flowing from long smooth nozzles. The results of calculations are compared with experimental data.

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Section: Introductionmentioning

confidence: 90%

Evaluating the critical velocity of air entrainment by plunging water jets

2023

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“…Studies that can be mentioned here include, for example, those by Lipari and Stansby 7 , who analyzed the issue of incompressible turbulent round jets issuing into a large, ideally infinite, quiescent domain. On the other hand, de la Torre et al 8 addressed the process of a circular free-falling jet entering an idle pool. Abdel-Rahman 9 considered the initial and boundary conditions affecting the jet.…”

Section: Introductionmentioning

confidence: 99%

Pressure distribution on a flat plate in the context of the phenomenon of the Coanda effect hysteresis

Skotnicka-Siepsiak

2022

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As a result of the Coanda effect, a symmetrical free jet will flow as an asymmetrical wall jet. At the same time, at the obstacle along which the flow is observed, the wall jet generates pressure distribution. In this study, the obstacle located at the diffuser outlet is a flat plate with a variable inclination angle. The article presents results of the study on pressure distributions on a flat plate with a variable angle of inclination. In the experiment, the Reynolds number ranged from 16,192 to 42,240. A fixed geometry diffuser (Witoszyński nozzle) with a height of 0.60 m, width of 0.02 m and outlet velocity of 11.33–29.57 m/s was used. A plate with a length of 1.00 m and a variable inclination angle was installed at the diffuser outlet. What is new, however, is that the presented results of the experimental research include the influence of the Coanda effect hysteresis on the pressure distribution on the plate. The article shows how pressure distributions change on the plate depending on whether the initial angle of inclination was 0° and was increased gradually in the course of the experiment until a detachment of the jet flowing from the plate was observed, or the initial angle of inclination was close to 90° in the primal state and as the angle of the plate inclination was decreased, the jet flowing towards the plate reached the state of attachment to the plate surface. The study demonstrated that for a turbulent jet, pressure distribution on a flat plate is determined not only by the plate’s inclination angle, but also by the direction of its rotation.

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“…The mechanism of air bubble formation for a plunging jet to a water pool has been studied experimentally in the literature where most studies focused on the average and global dynamic behaviour of the air/water mixture under the free liquid surface as the result of the plunging jet flow (Zhu et al 2000, Kiger and Duncan 2012, Qu et al 2013, Miwa et al 2018, Ramirez de la Torre et al 2020. The air entrainment phenomenon depends on the physical properties of the fluids, geometrical characteristics of the plunging jet system, and operational conditions such as fluid velocity (Metzger andKind 2015, Wang et al 2018).…”

Section: Introductionmentioning

confidence: 99%