O presente trabalho é dedicado ao desenvolvimento e implementação de uma estrutura computacional para realizar simulações numéricas de escoamentos turbulentos sobre geometrias complexas a baixo número de Mach. O algoritmo em análise é baseado em um esquema de integração no tempo preditor-corretor clássico, que utiliza um método de projeção para as equações de transporte de quantidade de movimento. A estratégia de decomposição de domínio é adotado para computação distribuída, exibindo níveis muito satisfatórios de aumento de velocidade e eficiência. A Metodologia da Fronteira Imersa é utilizada para caracterizar a presença de uma geometria complexa. Este método exige duas malhas computacionais separadas: Uma Euleriana, onde as equações de transporte são resolvidas com o método do Volume finito, de discretização de segunda ordem e um domínio Lagrangiano, representado por uma malha tipo casca não-estruturada que representa a geometria imersa. O código desenvolvido foi totalmente verificado pelo método das Soluções Manufaturadas, em ambos os domínios Euleriano e de Lagrangiano. As capacidades da estrutura computacional resultante são ilustradas em quatro casos distintos: um jato turbulento, o escoamento de Poiseuille, como uma questão de validação da Metodologia da Fronteira Imersa implementada, o escoamento sobre uma esfera, que abrange uma ampla gama de números de Reynolds, e finalmente, com a intenção de demonstrar a aplicabilidade da metodologia das Simulações das Grandes Escalas - LES - em um problema industrial, o escoamento turbulento dentro de um ventilador industrial.

The present work is devoted to the development and implementation of a computational framework to perform numerical simulations of low Mach number turbulent flows over complex geometries. The algorithm under consideration is based on a classical predictor-corrector time integration scheme that employs a projection method for the momentum equations. The domain decomposition strategy is adopted for distributed computing, displaying very satisfactory levels of speed-up and efficiency. The Immersed Boundary Methodology is used to characterize the presence of a complex geometry. Such method demands two separate grids: An Eulerian, where the transport equations are solved with a Finite Volume, second order discretization and a Lagrangian domain, represented by a non-structured shell grid representing the immersed geometry. The in-house code developed was fully verified by the Method of Manufactured Solu- tions, in both Eulerian and Lagrangian domains. The capabilities of the resulting computational framework are illustrated on four distinct cases: a turbulent jet, the Poiseuille flow, as a matter of validation of the implemented Immersed Boundary methodology, the flow over a sphere covering a wide range of Reynolds numbers, and finally, with the intention of demonstrating the applicability of Large Eddy Simulations - LES - in an industrial problem, the turbulent flow inside an industrial fan.

In this paper, numerical simulations of incompressible flows around rotating circular cylinders have been performed. The two-dimensional Navier-Stokes equations are solved by using a Cartesian non-uniform grid. The Immersed Boundary Method (IBM) with the Virtual Physical Model (VPM) was used in order to model the presence of the circular cylinder in the flow. The fractional time step method was used to coupling the pressure and velocity fields. The simulations were carried out for Reynolds numbers equals to 60, 100 and 200 for different specific rotations. The effects of rotation on flow characteristics and fluctuating forces were investigated. The Strouhal number, obtained by performing the Fast Fourier Transform (FFT) of the temporal distribution of the lift coefficient, and the pressure coefficients, were also been calculated. Vorticity contours are presented considering different values of the Reynolds number and specific rotation. The numerical results obtained are compared to those obtained by other authors and the usefulness of the numerical methodology composed by the combination of the IBM with the VPM to simulate flows in the presence of mobile bodies is highlighted.

This paper presents an immersed boundary formulation for three-dimensional incompressible flows that uses the momentum equation to calculate the Lagrangian force field indirectly imposing the no-slip condition on solid interfaces. In order to test the performance of this methodology the flow past a sphere for Reynolds numbers up to 1,000 have been calculated. Results are compared with numerical data from other authors and empirical correlations available in the literature. The agreement is found to be very good.

This paper presents a two-dimensional numerical simulation of flows around different bluff bodies, at Re = 100 and 200, using the Immersed Boundary (IB) method, as a sequence of a previous work. The force density term required by the IB method is obtained with the Virtual Physical Model (VPM). Simulations were carried out for two circular cylinders of different diameter in tandem, two cylinders of the same diameter in tandem and two cylinders placed in side by side arrangement. The configurations of seven cylinders in a 'V' arrangement, for angles of 40o < alpha < 180o, were also simulated. A configuration of 23 different bluff bodies, representing a transverse cut in a central tower of an offshore structure, has been also simulated and the results were compared with a single compact square, of equivalent size. The Strouhal number, the drag and the lift coefficients were also calculated. The Strouhal number is calculated using the Fast Fourier Transform (FFT) of the lift coefficient temporal distribution. Visualization of the vorticity and pressure fields and the streamlines are presented for each simulation showing the flow dynamics and patterns. It was possible to verify that the IB method with VPM is a powerful methodology to simulate flows in the presence of complex geometries.