NUMERICAL ANALYSIS OF THE FLOW BEHAVIOR PAST AN AHMED BODY WITH VARYING FRONT RADIUS CURVATURE AND ITS IM- PLICATIONS IN THE AERODYNAMIC FORCES.

Resumo

The objective of the present study is to evaluate the dynamics of the air flow past the well-known Ahmed
body benchmark where its original geometry has been changed. The modification consists in changing only the
front radius curvature; 4 additional curvatures were evaluated. These 5 different geometries were evaluated for
4 different flow velocities, so that the Reynolds Number ranged from 4.8x103
to 4.8x104
. The simulations were
performed in the transient regime. The initial condition of the transient model is the result of the equivalent steady
state model. Regarding the numerical schemes, the second order upwind was employed for the discretization of
the Navier-Stokes advective terms, PISO algorithm for the pressure-velocity coupling and second order backward
integration for the transient term. The k-omega SST standard OpenFOAM implementation was used as turbulence

model. The local flow behavior at the frontal part of the Ahmed body, like boundary layer detachment and reat-
tachment, as well as the its global physical behavior are exploited and correlated to the changes in the aerodynamic

forces.