For the experiment (dot), the [alpha] difference between flow crest (t/T = 0.21) and flow trough (t/T = 0.71) is not obvious and even the crest flow strength is much larger than that at flow trough (Figure 3), because many sediments picked up at the flow crest are still in movement at the flow trough.
Although both EF76 and ZF94 can predict the experiments near the flow trough (t/T = 0.6~0.8), they much overestimate the experiments near the flow crest (t/T = 0.21).
Corresponding to the concentration due to phase-lag, the experimental [[PHI].sub.d] never decreases to zero near the flow reversal in Figure 3, and the value near the flow crest is close to that near the flow trough. The two-phase model predicted computed [[PHI].sub.d] agree very well with the experiments for nonzero duration and the magnitude increment with D.
Near the flow trough, both EF76 and ZF94 can predict well due to the agreement of concentration.
"As far as South Stream - we always have insisted that there aren't any major problems with this one - the 17 B cubic meters of gas will flow trough
the current pipes of Bulgargaz, which we own 100%, while the remaining volume up to 63 B cubic meters will go trough the new South Stream pipes.