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hydrodynamic component of the pressure gives the required separation at the
crest. The model has yet to be applied to sediment suspension modelling.
Figure 22. Schematic depicting the theoretical discretisation of the
vorticity generated at a boundary wall. The dark, spots represent discrete
vortex elements that sum to model the effect of the diffuse vorticity cloud
(shaded area). Some problems for discrete vortex modelling of free shear
layers are where to place the first vortices after the salient edge and how
to set criteria for the free streamline.
Figure 23. Thomas et al (1983). Bubble trajectories computed near a line
vortex. Notice that a narrow band of X starting points lead to bubble
capture.
Figure 24. Thomas et al (1983). Dependence of the trapping width on the
vortex strength parameter for discreta with various specific gravities.
Figure 25. Thomas et al (1983). Comparison between computed and experimental
trapping width with vortex strength for bubbles in water.
Figure 26. Thomas et al (1983) . Examples of the developing shear layer after
a splitter plate at various times, as computed using the discrete vortex
method.
Figure 27. Thomas et al (1983). Computational simulation of bubble
trajectories in counter-buoyancy flow (buoyancy force is right to left, flow
left to right in this figure) . Notice that the model allows capture of
bubbles (signified by the cycloid-like trajectories). In such flows this
capture delays detrainment of the bubbles into the outer flows. Compare this
with the regions of high bubble voidage in figure 16.
Chapter 1: Appendix 1
Figure 1. Utami & Ueno (1987). Conceptual model of the horseshoe vortices
iv