부산대학교 도서관

Splitter plates attached to a cylinder looking like hair (SPCH) is one of the self-adaptive devices used to control actual flow conditions, which in turn interact with Aeolian tones constituting a typical case of study in engineering industries. The direct numerical simulation of the sound waves stimulated by such devices is a complicated task due to the small levels of sound pressure and the time-consuming existing solvers. However, the Cumulant Lattice Boltzmann Method (LBM) provides stability and robustness at high Reynolds numbers and carries out these simulations satisfactorily. First, the fundamental acoustical properties of the Cumulant LBM are studied in this paper. Propagation of point and planar acoustic waves is considered including the temporal decay of a standing plane wave, the spatial decay of a planar acoustic pulse, and the propagation of spherical waves. Then, the Cumulant LBM as a fluid flow solver is coupled with a Finite Element structural mechanics solver to predict the effects of SPCH on the noise generated by cylinders at high Reynolds numbers as a practical fluid structure interaction (FSI) application. The spectral modification and possible acoustic damping impact of such flaps, plus the sound propagation from one and two circular cylinders are studied. A comparison of the theoretical and numerical results shows a reasonable capability of the Cumulant LBM to predict acoustical events with small errors in dissipation and dispersion. Furthermore, the results show that SPCH alter the phase of the vortex shedding cycle and decrease the transversal distance from the center line of the shed vortices. Flaps, thus, control the wake generated past a cylinder and have an effective impact on decreasing sound generation. [ABSTRACT FROM AUTHOR]