Flow patterns and draining films created by horizontal and inclined coherent water jets impinging on vertical walls

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

“…the measured value of R, as reported by Wang et al (2013b), the Perspex and polypropylene fitted the relationship Rc = 4R/3 reasonably well, while the glass data followed Rc = 2R more closely. When the Rc data were plotted against 4R*/3, where R* is the value predicted by Equation [4] and which includes the contribution from the substrate via the advancing contact angle, Figure 6 shows that all three data sets showed good agreement.…”

“…In section 4, we compare the predictions of the models of Wilson et al (2012), Wang et al (2013b), Mertens et al (2005) and our model which is based on that of Mertens et al (2005) with our experimental data for the four different flow zones described in Figure 1. The predictions and hypotheses of these different models are discussed.…”

“…Contact angles measured under quiescent conditions, whether retreating or advancing, are unlikely to give a full description of the contact line. Wang et al (2013b) presented a first order model for the width of the rope which underestimated the measured values. The complexity of the physics at the contact line renders a full computational simulation, including the free surface, a demanding task.…”

“…Models for Zone I where the jet does not impinge normally are reported in Wang et al (2013bWang et al ( , 2015.…”

“…Knowledge of this wetting behaviour is important for cleaning operations involving walls and inclined surfaces, as the removal of soiling layers or contaminants is determined by a combination of shear stress, material transport, and soaking (time spent in contact with cleaning solution) (Wilson, 2005). This paper follows on from a series of studies of the flow behaviour and cleaning performance associated with liquid jets impinging on vertical and inclined walls (Wilson et al, 2012;Wang et al, 2013aWang et al, , 2013bWilson et al, 2014;Wang et al, 2015). The series builds on a model presented in Wilson et al (2012) which uses a relatively simple momentum balance to describe the geometry and velocity field of the radial flow zone surrounding the impingement point (see below).…”