Immersed boundary method and virtual physical model for onset turbulence flow around complex geometry / Método de fronteira imersa e modelo físico virtual para fluxo de turbulência de início em torno de geometria complexa

Abstract

An immersed boundary method is development for the fluid-body interaction, being consider the heat-transfer for the onset turbulence in two-dimensional (2D) thermofluid dynamics around isothermal complex geometries immersed in incompressible Newtonian flows. The fluid motion and temperature are defined on a fixed Eulerian grid, while the immersed body is defined on a Lagrangian grid. A virtual physical model is used for the diffusion of interfacial forces within the flow, guarantees the imposition of the no-slip boundary condition. This model dynamically evaluates not only the force that the fluid exerts on the solid surface, but the heat exchange between them. Therefore, this work presents the Navier-Stokes equations, together with the energy equation, under physically appropriate boundary conditions. To calculate the turbulence viscosity, was used the Smagorinsky model, implemented in the context of the Large Eddy Simulation (LES) model. This work confirms that, downstream of the immersed body, the recirculation: 1) increases with the increase in the number of Reynolds, keeping the numbers of Richardson constant, and 2) decrease with the increase in the number of Richardson, preserving the number of Reynolds constant. It also confirms the generation of the thermal plumes moving upwards. The results are compared with previous numerical results, considering different Reynolds numbers.