Air-assisted impact of water drops on a surface

Singh, Ramesh Kumar; Mandal, Deepak Kumar

doi:10.1007/s00707-019-02438-3

Cited by 4 publications

(7 citation statements)

References 27 publications

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“…So, a sudden fall is witnessed at higher airflow and Weber numbers . The drop starts moving in the vertical direction, resulting in thicker finger formation …”

Section: Introductionmentioning

confidence: 99%

“…28 So, a sudden fall is witnessed at higher airflow and Weber numbers. 39 The drop starts moving in the vertical direction, resulting in thicker finger formation. 39 However, the studies of the airflow-assisted impact of drops are conducted for water drops of given viscosities only.…”

Section: ■ Introductionmentioning

confidence: 99%

“…39 The drop starts moving in the vertical direction, resulting in thicker finger formation. 39 However, the studies of the airflow-assisted impact of drops are conducted for water drops of given viscosities only. 1,23,39 The influence of the drop's viscosity on spreading is scantly investigated till now for the airflow-assisted impacts, although it is known that the incident airflow provides a shear force and normal imposed pressure on the drop.…”

Section: ■ Introductionmentioning

confidence: 99%

“…It is reported that the spreading always rises when the airflow is incident . The incident airflow provides a normal imposed pressure and a shear force on the drop. , An effective rise occurs only when the work done by the air pressure becomes larger than 10% of the drop’s kinetic energy for low impact Weber numbers (= ).…”

Section: Introductionmentioning

confidence: 99%

“…However, the spreading does not always increase with the Reynolds number of air; the combination of the rise in the impact Weber number and the Reynolds number of air increases the deceleration rate and restricts the radial movement of the drop . So, a sudden fall is witnessed at higher airflow and Weber numbers . The drop starts moving in the vertical direction, resulting in thicker finger formation …”

Section: Introductionmentioning

confidence: 99%

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Airflow-Assisted Impact of Drops of Various Viscosities: The Role of Viscous Dissipation, Normal Imposed Pressure, and Shear Flow of Air

2021

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The role of liquid viscosity on the spreading for an airflow-assisted impact of drops on a surface is investigated. The spreading diameter is found to increase with the Reynolds number of the airflow (Re air ) for a given viscosity and impact Weber number (We) compared to the still air. The increment is higher at a low We for viscous drops, whereas the effect of Re air dominates at the intermediate We as the viscosity decreases. Two extra forces, the normal imposed pressure and shear force of air, act on the drop and influence the spreading along with the viscous dissipation. The drop's curvature decreases depending on the viscosity and impact velocity while spreading. Large-scale eddies near the drop-surface region are observed due to the separation of the incident airflow. The formation of eddies signifies lowpressure zones, which extract the trapped air, causing the spreading diameter of the viscous drop to increase at a low We. With the increase in the We, the lamella thickness of low-viscosity drops decreases and is pushed out by the air shear causing the spreading factor to increase. The boundary layer thickness is estimated using the energy balance method to predict the maximum spreading factor. The prediction compares well with the experimental one for higher viscosities. The accuracy improves when the effect of low pressure is incorporated. To confirm, the experimental spreading is compared with that obtained from three existing models, and one, which considers the influence, is observed to provide a better prediction.

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“…So, a sudden fall is witnessed at higher airflow and Weber numbers . The drop starts moving in the vertical direction, resulting in thicker finger formation …”

Section: Introductionmentioning

confidence: 99%