円転円板による容器内流れの不安定性と遷移過程

概要

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The characteristics of instabilities and the transition processes to turbulence are studied experimentally for the flow between a rotating disk and its casing. The spectral analyses of the velocity fluctuations show that, in the case of a larger clearance ratio (s/R=0.080), an inviscid instability of the boundary layer flow on the rotating disk starts at the local Raynolds number Re_L(=r^2ω/ν) of about 8×10^4, which is in good agreement with that obtained theoretically in our previous work. Visualization of the flow near the rotating disk reveals that two different types of instabilities occur at any clearance ratio tested (s/R=0.016〜0.160). It is believed that one of these is a viscous type and the other is an inviscid type. The characteristics of these instabilities are compared with those predicted by a linear stability analysis. The transition processes to tubulence are clarified for two different clearance ratios (s/R=0.080, 0.016) in view of the velocity power spectrum.
社団法人日本機械学会の論文
1988-06-25