Case 1 results
Graphical results obtained from the four tests conducted with a discharge
scale of NQ =1.5 are presented here as representative of this test configuration.
Complete graphical results for all 12 tests are included in Appendix A.
Measured velocity vectors for the prototype case are shown in Figure 21,
and the corresponding results from models with distortion 2, 4, and 6 are shown
scaled up to prototype in Figures 22, 23, and 24, respectively. Scaling was
performed using the scale factors presented in Table 5. A similar distinct jet flow
with low velocity entrainment adjacent to the jet is seen in all the velocity vector
plots.
Comparison between prototype and distorted models was done visually by
superimposing vector diagrams from two experiments. Figure 25 plots the vector
fields from the prototype and the distortion 6 model tests at actual scale to give
an idea of the horizontal length scale difference between the two experiments.
A similar comparison with distorted model results scaled to prototype size is
shown in Figure 26 with the distorted model results displaced slightly to the right
of the prototype results. As seen, the comparison between prototype and
distorted model is favorable, even in the slow-moving flow entrainment region;
and current patterns seem to be reproduced well in this configuration despite the
presence of strong horizontal turbulence in the flow. Similar good agreement
was found for comparisons between prototype and all distorted models at all flow
rates as shown by the plots in Appendix A.
The ratio between prototype and scaled-up velocity components was
determined at each measured point in the flow. Ratios of the cross-flow velocity
components for experiments with discharge scale NQ = 1.5 are presented in
Figure 27, and the corresponding ratios in the principal flow direction are plotted
in Figure 28. Perfect correspondence would be represented by horizontal lines
with no deviations.
The ratio plots enable recognition of spatial positions where similitude might
be in question. Variations shown in the crossflow direction (Figure 27) are likely
caused by taking the ratio of very small velocities; and consequently, much of the
variation could be measurement inaccuracy. Good similitude is seen in the
principal flow direction as illustrated in Figure 28 where the only significant
deviation appears near the boundary of the jet and ambient fluid. Some of this
variation might be caused by measuring at slightly different positions along the
jet boundary where there is a steep velocity gradient. Given the amount of flow
turbulence generated at the jet boundary, these experiments indicated good
similitude existed between the prototype and distorted models. Similar
comparison plots for the other Case 1 experiments are in Appendix A.
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Chapter 5 Turbulence Scale Effects Experiments
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