Particle image velocimetry and modelling of horizontal coherent liquid jets impinging on and draining down a vertical wall

Aouad, Wassim; Landel, Julien R.; Dalziel, Stuart B.; Davidson, John; Wilson, D.I.

doi:10.1016/j.expthermflusci.2015.12.010

Cited by 22 publications

(13 citation statements)

References 25 publications

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“…If one considers the phase diagram of Ghezzehei (2004), contact angles of 70° for the acrylic Plexiglas used (e.g. Aouad et al 2016;Della Volpe et al 2002;Sumner et al 2004) at the flow rates tested, rivulets and sliding droplets should dominate the observed flow mechanisms. The observation of coexisting droplet and rivulet flow mechanisms is likely a function of the test set-up, and not due to the same process as presented by Dragila et al (2016).…”

Section: Resultsmentioning

confidence: 99%

Assessing geotechnical centrifuge modelling in addressing variably saturated flow in soil and fractured rock

Jones

Brouwers

Tonder

et al. 2017

Environ Sci Pollut Res

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The vadose zone typically comprises soil underlain by fractured rock. Often, surface water and groundwater parameters are readily available, but variably saturated flow through soil and rock are oversimplified or estimated as input for hydrological models. In this paper, a series of geotechnical centrifuge experiments are conducted to contribute to the knowledge gaps in: (i) variably saturated flow and dispersion in soil and (ii) variably saturated flow in discrete vertical and horizontal fractures. Findings from the research show that the hydraulic gradient, and not the hydraulic conductivity, is scaled for seepage flow in the geotechnical centrifuge. Furthermore, geotechnical centrifuge modelling has been proven as a viable experimental tool for the modelling of hydrodynamic dispersion as well as the replication of similar flow mechanisms for unsaturated fracture flow, as previously observed in literature. Despite the imminent challenges of modelling variable saturation in the vadose zone, the geotechnical centrifuge offers a powerful experimental tool to physically model and observe variably saturated flow. This can be used to give valuable insight into mechanisms associated with solid-fluid interaction problems under these conditions. Findings from future research can be used to validate current numerical modelling techniques and address the subsequent influence on aquifer recharge and vulnerability, contaminant transport, waste disposal, dam construction, slope stability and seepage into subsurface excavations.

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Section: Resultsmentioning

confidence: 99%

Assessing geotechnical centrifuge modelling in addressing variably saturated flow in soil and fractured rock

Jones

Brouwers

Tonder

et al. 2017

Environ Sci Pollut Res

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“…Measurements of the velocity profile in these films are complicated by the presence of surface waves. Aouad et al (2016) measured the surface velocity in the RFZ for jets impinging perpendicularly on vertical walls using particle image velocimetry. They used a dye to limit measurements to the surface region alone.…”

Section: Perpendicular Impingement (ϕ = 90°)mentioning

confidence: 99%

“…Wilson et al (2012) presented a model for the flow in the RFZ which gave good agreement with Morison and Thorpe's data for the width at AA′, marked R j,90 in Figure 1, as well as new experimental data sets. The dimensions of the RFZ for obliquely impinging jets and the behaviour below have since been investigated by Wilson and co-workers (Wilson et al, 2012;Wang et al, 2013a,b;Wang et al, 2015;Aouad et al, 2016) and by other groups (e.g. Gordeev et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Flow in the thin film created by a coherent turbulent water jet impinging on a vertical wall

Bhagat

Wilson

2016

Chemical Engineering Science

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When a liquid jet impinges on a vertical wall it forms a thin film which flows radially away from the point of impingement until a point where the outward momentum is balanced by surface tension and a film jump is formed. The model for the location for the film jump presented by Wilson et al. (Chem. Eng. Sci, 2012, Vol. 68, pp 449-460) is revised to include the development of laminar and turbulent boundary layers in the thin film. The criterion for film jump formation is also revisited, and the analysis explains why the location is insensitive to the nature of the wall material at high flow rates. The model is compared with published data for velocity profiles in the thin film, the transition to turbulence, and new experimental data where the average velocity in the thin film was estimated from the initial growth of the radial flow pattern for flow rates of 1.95 to 4.01 dm 3 s-1 , corresponding to jet Reynolds numbers of 15 500 to 32 000. Very good agreement with the published and measured data is obtained, with no adjustable parameters, for jets impinging perpendicularly as well as at an oblique angle. The model shows that the parabolic velocity profile assumed by Wilson et al. gives a reasonable estimate of the average velocity, but it is not able to predict phenomena such as the observed transition to turbulence.

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“…Above the point of impingement this gives rise to a film jump with a narrow band (or rope) of liquid which flows circumferentially downwards beyond it. Below the point of impingement, gravity causes this this initial jump to evolve into a draining film, bounded by the ropes which join from above and form the boundaries of the falling film (Aouad et al, 2016;Bhagat et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Much of the work on impinging jet hydrodynamics (e.g. Watson, 1964;Bush and Aristoff, 2003;Wilson et al, 2012;Aouad et al, 2016) has employed coherent jets impinging normally on flat walls. The jets employed in practice are subject to several phenomena which affect the transfer of those results to industrial systems.…”

Section: Introductionmentioning

confidence: 99%

Impinging jet cleaning of tank walls: Effect of jet length, wall curvature and related phenomena

Chee¹,

Ahuja²,

Bhagat³

et al. 2019

Food and Bioproducts Processing

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The effect of jet length and wall curvature on the flow patterns generated by an impinging water jet were quantified and the effect on cleaning investigated in a brief study. The length of time taken to establish steady flow was characterised. Jet impingement on a flat vertical wall was investigated for jets of diameter 2-4 mm for lengths, L, up to 1 m. The amount of liquid lost to splatter was measured and found to be insensitive to L for short L (< 300 mm for these nozzles) and strongly related to L for longer values. The shape of the radial flow zone on flat walls agreed with existing models once the fraction of liquid lost to splatter was accounted for. Tests on horizontal and vertical cylinders with curvatures in the range 6.9 to 20 m-1 showed that the curvature of the impinged wall did not affect the shape of the radial flow zone until higher flow rates (> 1.5 dm 3 min-1). The cleaning of two viscoplastic model food soils was studied briefly: a hydrophobic petroleum jelly and Carbopol ® , a water-soluble gel. The splatter correction was not able to account for all the differences observed in cleaning at different jet lengths. There was no appreciable effect of curvature on cleaning behaviour. Soaking of the Carbopol ® increased its cleaning rate.

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Particle image velocimetry and modelling of horizontal coherent liquid jets impinging on and draining down a vertical wall

Cited by 22 publications

References 25 publications

Assessing geotechnical centrifuge modelling in addressing variably saturated flow in soil and fractured rock

Assessing geotechnical centrifuge modelling in addressing variably saturated flow in soil and fractured rock

Flow in the thin film created by a coherent turbulent water jet impinging on a vertical wall

Impinging jet cleaning of tank walls: Effect of jet length, wall curvature and related phenomena

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