Resumo:
The aim of this work is to simulate numerically the two-dimensional, incompressible,
unsteady flow around a body of arbitrary shape in the presence of a ground plane. The fluid is
Newtonian, with constant properties. This problem can be considered as a preliminary study
to analyze the global flow that develops in turbomachines due the rotor/volute interference.
As an initial approximation, the rotor motion inside the volute can be interpreted as the
motion of an airfoil in the vicinity of a ground plane. A new methodology using the discrete
vortex method is presented, being possible to analyze the effects of the interaction of the
airfoil and the ground-plane wakes. The airfoil surface is simulated by straight-line panels,
with constant-strength vortex distribution. The vorticity generated on the airfoil and ground
plane surfaces is replaced by Lamb vortices located near the surfaces. The wake dynamics is
computed using the convection-diffusion splitting algorithm, where the convection process is
carried out with a lagrangian second order time marching scheme (Adams-Bashforth scheme),
and the diffusion process is simulated using the random walk method. The physical
characteristics of the airfoil and ground-plane wake interaction are identified and analyzed;
results for the aerodynamics loads are presented and comparisons are made with other results
available in the literature.
