Lattice Boltzmann Study of Flow Fields Around Stationary and Oscillatory Cylindrical Objects in Various Arrangements

Abstract

Computational fluid dynamics is a fascinating and complex subject due to rapid development of computer technology, high level programming languages and new developed numerical techniques for unlimited set of different engineering applications. The study of wake structure mechanism behind the cylindrical objects is important for practical applications in wind engineering, aerodynamics, and electronics cooling. The main objective of this study is to systematically investigate the stationary and oscillatory flow problems using the lattice Boltzmann method. The oscillating flow fields are common flow fields in many practical situations like ocean engineering, off-shore structures and similar type of bodies located in a wave environment. Oscillatory motions of small amplitude are very important in the analysis of immersed vibrating bodies. Such motions alter the aerodynamic forces and the pressure distributions as compared to those of rigid body. This may also result to the lock-in phenomenon, where the shedding frequency of fluid becomes equal to the oscillating frequency of the object. On the other hand the oscillatory motions of larger amplitude alter the far flow fields which can be affective due to the presence of other bodies in the flow field. Therefore detailed information regarding the variations of flow fields due to oscillatory motions is very important for designing structures. This study will focus on three main points: (a) Flow past stationary cylinder at various arrangements, (b) Drag reduction in terms of small control cylinders (c) Flow characteristics of oscillatory cylinder arranged in side-by-side or tandem. All these results, most of which have been obtained for the very first time, are of fundamental significance in engineering applications