NUMERICAL SIMULATION OF THE FLOW AROUND THE AHMED VEHICLE MODEL

FRANCK GERARDO; NIGRO NORBERTO; STORTI MARIO; D'ELIA JORGE

LATIN AMERICAN APPLIED RESEARCH

PLAPIQUI(UNS-CONICET)

Año: 2009 vol. 39 p. 295 - 306

0327-0793

The unsteady flow around the Ahmedvehicle model is numerically solved for a Reynoldsnumber of 4.25 million based on the model length. Aviscous and incompressible fluid flow of Newtoniantype governed by the Navier-Stokes equations is assumed.A Large Eddy Simulation (LES) technique isapplied together with the Smagorinsky model asSubgrid Scale Modeling (SGM) and a slightly modifiedvan Driest near-wall damping. A monolithiccomputational code based on the finite element methodis used, with linear basis functions for bothpressure and velocity fields, stabilized by means ofthe Streamline Upwind Petrov-Galerkin (SUPG)scheme combined with the Pressure Stabilizing Petrov-Galerkin (PSPG) one. Parallel computing on aBeowulf cluster with a domain decomposition techniquefor solving the algebraic system is used. Theflow analysis is focused on the near-wake region,where the coherent macro structures are estimatedthrough the second invariant of the velocity gradient(or Q-criterion) applied on the time-average flow. Itis verified that the topological features of the timeaverageflow are independent of the averaging timeT and grid-size