Periodically Oscillating Turbulent Flows in the Entrance Region of a Curved Rectangular Duct

概要

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Fluctuation of the boundary layer grown on the end plate of a curved duct is studied experimentally for two inlet flow conditions: uniform flow which fluctuates sinusoidally in magnitude and flow which always has a fully developed duct flow profile but which fluctuates in magnitude. For both cases, the cross-sectional mean Velocity, U_m, fluctuates with the Womersley number of 44.3, the ratio of the amplitude of U_m to its time mean value, U^^-_m, is 0.38, and the Dean number based on U^^-_m is 1.28×10^4. It is found that (1) at the cross section of the duct turning angle of 60°, the fluctuation of the momentum thickness of main flow velocity, U_φ, is very much different with the two inlet conditions, and (2) the distribution of U_φ shows very good agreement with the 1/n power law but flow fluctuation has a great effect on the distribution of the cross-flow velocity component, U_r, very close to the wall.
一般社団法人日本機械学会の論文
1990-05-15