ALE手法を用いた運動する車両周りの非圧縮性LES解析 : 第2報,振動円柱周りの流れ場での精度検証(流体工学,流体機械)

概要

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LES (large eddy simulation) of flows around a forced-oscillating circular cylinder is conducted using an ALE (arbitrary Lagrangian-Eulerian) method. For stable calculations without numerical viscosity, a discretization method which improves the conservation properties of the mass, momentum and kinetic energy in ALE coordinates, is employed. The Reynolds number based on the cylinder diameter is set to 8000. The cylinder is oscillated sinusoidally in the transverse direction with non-dimensional amplitude of 0.2 and frequencies ranging from 0 to 0.27. The results are compared with the measurements that are also carried out by authors, in terms of lock-in phenomenon. It is shown that the numerically predicted time-averaged pressure distributions and phase-averaged velocity distributions are in good agreement with the experimental data, both in the lower and the upper lock-in region. In addition, the phase difference between the cylinder displacement and the vortex shedding is consistent with previous findings. It is also clarified that the frequency range of the lock-in in LES with the present discretization method is almost the same as that of the experiment in width, while it becomes wider in the comparative calculation, where the QUICK scheme is employed for the convection terms. Such discrepancies between two calculations are prominent, especially in the stationary state and the lower frequency region.
2010-06-25