Figure 4
From: Understanding turbulent free-surface vortex flows using a Taylor-Couette flow analogy
Spatio-temporal map representing the magnitude of the axial velocity along the z–axis for a approximately 0.3 seconds is highlighted in (a) which was achieved using (b) transducer 4 positioned at 80.5 mm away from the vessel perimeter. Based on observations of the velocity vector maps, the vertical transducer 4 provided a profile which was likely to pass through the regions of Taylor-like vortices. The counter rotating Taylor-like vortices are represented on the (a) spatio-temporal colour map by the negative, positive and negative radial bands which appear to span the extent of the z–axis indicating areas of alternating rotation; a signature of the Taylor vortices. Figure 4(c,d) Presents the axial velocity profiles obtained using transducer 4 for h/d = 1.5 (M = 6.37 × 105) and h/d = 2.0 (M = 7.42 × 105) which highlight the signature for cellular structures in the secondary flow field. The radial velocity v r along the radius determined from transducer 8, positioned at 15 mm above the base, is highlighted for (e) h/d = 1.5 (M = 6.37 × 105) and (f) h/d = 2.0 (M = 7.42 × 105) highlighting inwards and outwards radial flow zones.
