Computational analysis of naturally oscillating tandam square and circular bluff boaies: a GPU based immersed poundary- lattice Boltzmann approach

초록

In this study, a fluid-structure interaction solver is employed to explore the flow physics of tandem oscillating square bluff bodies by varying the corner radius. Based on previous research, dynamic behavior, and fluid forces only square and circular bluff bodies are chosen fora supplementary investigation. This study investigates the effects of the streamwise displacement, 1.05 <= L-x/D <= 12.0, of two elastically mounted square and circular bluff bodies in a tandem arrangement. Fluid flows at a Reynolds number of 100 and a fixed mass ratio m* = 10 are used for the upstream and downstream bluff bodies. As the most complex oscillations and wake flows occur adjacent to the approximate natural frequency ratio, thus a constant natural frequency of F-r = 1.0 is defined. To achieve excellent parallel performance, an immersed boundary lattice Boltzmann method code coupled with a structural equation is developed and accelerated using a graphical processing unit. The results for flow-induced vibrations suggest that the flow response characteristics of the tandem oscillating bluff bodies are strong functions of the streamwise displacement. Four different flow regimes of the bluff body arrangements are identified on the basis of response amplitude. Both the square and circular downstream bluff bodies exhibit two peak transverse amplitudes in the existing scrutinized spacing ratios. In addition, the critical spacing ratio values are dissimilar for the two bluff bodies. Moreover, at the end of the spacing ratio (L-x/D >= 10), the wake effects for the downstream square body are amplified, and it oscillates near a single oscillating circular bluff body. Finally, the flow physics, as well as the hydrodynamic force coefficients of the tandem oscillating bluff bodies are also reviewed.

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