Previous laboratory experiments and associated numerical models of laminar flows forced by oscillatory, along-shelf background currents are extended to include some of the effects of boundary-generated turbulence. The experiments are conducted in the 13-m-diameter rotating-flow facility in Grenoble, France. Two pairs of case studies, one at a large forcing velocity (designated as FAST) for which the boundary layers are fully turbulent during part of the flow cycle and one at relatively smaller forcing (SLOW) for which transitional boundary layers are operative at the higher speeds of the background flow, are conducted. Smooth and artificially roughened boundaries are considered, respectively, for each of these pairs. Phase-averaged and time-mean velocity, vertical vorticity, and horizontal divergence fields are found to be qualitatively similar to those of previous laminar experiments. The similarities in the time-mean fields are that (i) within the canyon they are dominated by cyclonic vorticity with maxima centered near the shelf break; (ii) within and in the vicinity of the canyon the general circulation pattern includes a net transport into the canyon through its mouth, a net upwelling in the canyon interior, a transport away from the canyon over the shelf break along both sides of the canyon, and, by inference, a return flow to the deep ocean; and (iii) the interior time-mean flow is characterized by a well-defined coastal current whose axis follows the shelf in the vicinity of the shelf break, with the coast on the right. It is found that the measurements of the characteristic speed of the residual or time-mean flow within the canyon for the transitional and fully turbulent experiments do not follow the scaling law derived earlier for laminar experiments. An alternative scaling analysis for large-Reynolds-number flows is thus derived. Although sufficient numbers of experiments are not available to test the hypothesis fully, the measurements available for the fully turbulent flows are consistent with the theory advanced.

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Soot formation characteristics of ethylene-air turbulent partially premixed flames have been experimentally determined by measuring the soot volume fraction, via laser-induced incandescence. Measurements were made in the near-burner soot-forming region up to axial distance of 25 burner diameters. The amount of soot formed in these flames varies nonmonotonically as the equivalence ratio is lowered from that of non-premixed flames. Initial premixing with air results in a substantial increase in the integrated soot volume fraction, up to a factor of nearly 2 in comparison to non-premixed flames. Only at overall equivalence ratio near 10, the amount of soot is brought below the level of non-premixed flames in the region. Further premixing with air results in a continuous decrease in the soot volume fraction. The radial profiles of soot volume fraction show more evenly distributed soot particles in partiallypremixed flames, indicating that soot-forming regions are significantly broadened in these flames. The injection location of premixing air has a significant effect on the sooting characteristics of partially-premixed flames. In the current co-axial jet flame burner configuration, when the premixing air is added co-axially at the burner exit plane, the partial premixing always resulted in a decrease in the integrated soot volume fraction. Moving the injection point upstream caused the amount of soot to increase rapidly. The pdf's of the soot volume fraction are consistent with the above observations in that there is a shift in the pdf toward larger soot volume fraction when there is an increase in the integrated soot volume fraction. Except, the effect of the air injection location is manifest through small but finite probabilities of large soot volume fractions, while the peak of the pdf remains at small soot volume fractions. These results point out some important trends in the sooting characteristics as a function of partial premixing parameters.