E204 2×2ロッドバンドル内乱流の速度分布(OS9 熱・流動(試験))

概要

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Validation of turbulence models is not an easy task mainly due to lack of experimental data on turbulent flows in rod bundles. In this study, we therefore measured distributions of velocity and turbulence intensities of water flows in a 2x2 rod bundle by using a PIV system. The diameter and pitch of the rods were 20 and 25mm, respectively. The mean velocity ranged from 1 to 2m/s. The local time-averaged velocity and turbulent intensities were obtained from 10,000 instantaneous velocity data at each measurement point. Time resolved PIV measurements were also carried out to obtain the turbulence spectra. As a result, the following conclusions were obtained: (1) The fluctuation of velocity component normal to the rod wall is weaker in the low wave number region than that of the perpendicular component in horizontal plane in the rod gap. (2) The distribution of Reynolds stress on the centerline of the test section has the trend similar to the gradient of stream wise velocity. This implies the validity of the eddy viscosity assumption.
一般社団法人日本機械学会の論文
2011-06-22