Taylor-Couette流における非線形軸方向波数選択

概要

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Direct numerical simulations of Taylor-Couette flows are conducted to clarify the axial wave number selection of two modes which have different growth rates in the Taylor-Couette flows. By investigating the energy transfer functions, the following conclusions are obtained. (1) In the initial stage, two modes which have different wave numbers grow independently, and the growth rates are determined based on the linear stability theory. However, the mode which is finally selected cannot be predicted using the linear stability theory. (2) The wave number selection of two modes, k_1 and k_2, depends on the nonlinear interaction with the wave number (k_1-k_2). The energy transfers to (k_1-k_2) from k_1 and k_2 play important roles in this process. The ratio between the energy transfer to (k_1-k_2) from k_1 and from k_2 is k_2 : k_1. (3) If the sum of energy transfer from mean flow, viscous dissipation and energy transfer due to the nonlinear interaction becomes negative for one mode, this mode is not selected in the final stage. The energy transfer due to the nonlinear interaction is determind by the energy level at the time when the nonlinearity becomes important.
一般社団法人日本機械学会の論文
1996-02-25