  The flow patterns created by a coherent horizontal liquid jet impinging on a
vertical wall atmoderate flow rates (jet flowrates 0.5-4.0 L min-1, jet
velocities 2.6-21 m s-1) are studied withwater on glass, polypropylene and
polymethylmethacrylate (acrylic, Perspex(R)) using a novelparticle image
velicometry (PIV) technique employing nearly opaque fluid doped withartificial
pearlescence to track surface velocity. Flow patterns similar to those reported
inprevious studies are observed on each substrate: their dimensions differed
owing to theinfluence of wall material on contact angle. The dimensions are
compared with models for (i)the radial flow zone, reported by Wang et al.
(2013b), and the part of the draining film belowthe jet impingement point where
it narrows to a node. For (ii), the model presented by Mertenset al. (2005) is
revised to include a simpler assumed draining film shape and an
alternativeboundary condition accounting for surface tension effects acting at
the film edge. This refinedmodel gives equally good or better fits to the
experimental data. The effective contact anglewhich gives good agreement with
the data is found to lie between the measured quasi-staticadvancing and
receding contact angles, at approximately half the advancing value. The
PIVmeasurements confirmed the existence of a thin fast moving film with radial
flow surroundingthe point of impingement, and a wide draining film bounded by
ropes of liquid below theimpingement point. While these measurements generally
support the predictions of existingmodels, these models assume that the flow is
steady. In contrast, surface waves were evident inboth regions and this partly
explains the difference between the measured surface velocity andthe values
estimated from the models.
