In order to evaluate three types of conveyance equipment using swirling flow, the flow fields in a vertical pipe were visualized by 3D-PIV and the three-dimensional velocity distributions were analyzed with modal wavelet transforms. The three types of equipment all have a main vertical pipe. Type A has one air inlet and an opening vertical pipe, Type B has four air inlets and an opening vertical pipe and Type C has four air inlets and a closing vertical pipe attached four air outlets. The 3D-PIV revealed that Type A and Type B exhibited an approximate axial flow along with a weak swirling flow. On the other hand, Type C had a strong swirling flow. As a result of modal wavelet transform analysis, it was found that the high frequency multiresolution element was the smallest in the Type C swirling component. This indicates that Type C has the steadiest swirling flow for suitable swirling conveyance equipment.

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Velocity field in the vicinity (< 600 micro-m) of a moving contact line was measured using the particle imaging velocimetry (PIV) technique. The experiments consisted of withdrawing a solid plate of different surface materials (glass, stainless steel, acrylic resin, and a superhydrophobic coating) from water into air, or from water into polydimethylsiloxan (PDMS), at a constant rate of 0.62 mm/s. The large difference in the surface wettability in these combinations of fluid and surface materials resulted in a variation of water contact angle from zero to 130 deg. The viscous continuum theory by Huh (1971), with the contact angle and the viscosity ratio between the upper and lower fluids given as the boundary conditions, failed to reproduce the measured velocity field. When the tangential velocity on the interface was forced to be the same as the measured value, the model reproduced well the measured velocity field.

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