A MESOSCOPIC MODEL APPROACH TO PASSIVELY CONTROL VORTEX WAKES USING SINGLE/MULTIPLE BODIES

摘要

In this paper, vortex patterns are studied when single or several objects are located in the bluff-body wakes. The suitability of a mesoscopic approach involving a single phase Lattice Boltz-mann (LB) model is examined. The central idea behind proposing the present formulation is to capture smaller scales naturally, postponing the need of applying empirical turbulence models. In contrast, to continuum mechanics based numerical models, where only space and time are discrete, the discrete variables of the LB model are space, time and particle velocity. With reference to the Boltzmann equation of classical kinetic theory, the distribution of fluid molecules is represented by particle distribution functions. It is notable that the formulation avoids the need to include the Poisson equation. An elastic-collision scheme with no-slip walls is prescribed. Although the long term goal is to predict bluff-body high Reynolds number flows, the present study is limited to laminar flow simulations. The case studies include sharp edge bodies embedded in Re flows in the order of 100-250. The 2-D uniform grid solutions are compared with findings reported in the literature and promising agreements have been found. This study is important to a variety of applications, in particular, the wind, ocean and coastal engineering communities. From a mitigation point of view, the model presents an easy means of re-arranging bluff bodies to study optimum solutions for VIV suppression. It is notable that the CPUs are favorable for the multiple bluff body solutions compared to current published continuum mechanics models.