制御噴流のDNSによる混合指標に関する検討(流体工学,流体機械)

概要

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To establish a good measure of mixing rate, DNS (direct numerical simulation) of the controlled jets are conducted. In the computation, the spatial discritization is performed by hybrid scheme in which sixth order compact scheme in streamwise direction and Fourier series in cross section are adopted. The Reynolds number is 1500. The mixing properties are estimated by two measures such as statistical entropy and mixedness parameter, which are constructed based on a scalar concentration. Compared with simple measure, i.e., means jet width, centerline velocity and turbulent kinetic energy, it is found that: (1) the statistical entropy is the good measure to describe the mixing state in different controlled jet, (2) the fluctuating statistical entropy distribution enable to express the highly mixed region, and (3) its production term correlates to the vortical structure. As well as the statistical entropy, the mixedness parameter also has useful properties for estimation of mixing efficiency. These findings suggest that these measures are expected to contribute to the optimazion of jet mixing.
一般社団法人日本機械学会の論文
2008-01-25