High-order LES of the flow over a simplified car model
On the influence of the Reynolds number
DOI:
https://doi.org/10.13052/EJCM.18.627-646Keywords:
large-eddy simulation, spectral methods, spectral vanishing viscosity, Ahmed bodyAbstract
We study the influence of the Reynolds number on the Ahmed body flow for the subcritical incidence . =25°. Large Eddy Simulations (LES) have been performed at low Reynolds number Re=8322, in agreement with the experiments of Spohn and Gillieron (2002), for the configuration used by Lienhart et al. (2002) at Re=768000. Our simulations, based on a spectral Chebyshev collocation-Galerkin Fourier method, have been carried out with a parallel multi-domain solver. The LES capability is implemented by a Spectral Vanishing Viscosity (SVV) technique. The results globally point out that the topology of the flow is essentially determined by the body geometry.
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References
Ahmed S.R., Ramm G. and Faltin G., "Salient Features of the Time-Averaged Ground Vehicle
Wake", SAE-Paper 840300, 1984.
Angot P., Bruneau C.H. and Fabrie P., "A penalization method to take into account obstacles
in incompressible viscous flows", J. Numer. Math., vol.81, 497, 1998.
Fares E., "Unsteady flow simulation of the Ahmed reference body using a lattice Boltzmann
approach", Computers & Fluids, vol.35, n°8-9, 940, 2006.
Guermond J.L., Oden J.T. and Prudhomme S., "Mathematical Perspectives on Large Eddy
Simulation models for turbulent flows", J. Math. Fluid Mech., vol.6, 194, 2004.
Guilmineau E., "Computational study of flow around a simplified car body", J. Wind
Eng.Ind.Aerodyn., doi :10.1016/j.jweia.2007.06.041, 2007.
Hinterberger M., Garcia-Villalba M. and RodiW., "Large Eddy Simulation of flow around the
Ahmed body", In Lecture Notes in Applied and Computational Mechanics / The Aerodynamics
of Heavy Vehicles : Trucks, Buses, and Trains, McCallen, R., Browand, F., Ross (Eds.),
J., Springer Verlag, 2004.
Kapadia S, Roy S. and Wurtzler K., "Detached eddy simulation over a reference Ahmed car
model", AIAA Paper 2003-0857 ; 2003.
Karamanos G.S. and Karniadakis G.E., "A spectral vanishing viscosity method for large-eddy
simulation", J. Comput. Phys., vol.163, n°22, 2000.
Kirby R.M. and Karniadakis G.E., "Coarse resolution turbulence simulations with spectral
vanishing viscosity - Large Eddy Simulation (SVV-LES)", J. Fluids Engineering, vol.124
(4), 886-891, 2002.
Khadra K., Angot P., Parneix S. and Caltagirone J.P., Fictitious domain approach for numerical
modelling of Navier-Stokes equations, Int. J. Numer. Meth. Fluids, vol.34, 651-684, 2000.
Krajnovic S. and Davidson L., "Large-Eddy Simulation of the Flow Around a Ground Vehicle
Body", SAE 2001 World Congress, Detroit, MI, USA, March 2001.
Krajnovic S. and Davidson L., "Flow around a simplified car", Journal of Fluids Engineering.
vol.127, 907-918 et 919-928, 2004.
Lienhart H., Stoots C. and Becker S., "Flow and turbulence structures in the wake of a simplified
car model (Ahmed Body)". New Results in Numerical and Experimental Fluid Mechanics,
-17 Nov., 2002.
Maday Y., Kaber S.M.O. and Tadmor E., Legendre pseudo-spectral viscosity method for nonlinear
conservation laws, SIAM J. Numer. Anal., vol.30, n°2, 321-342, 1993.
Manceau R. and Bonnet J.-P., "10th joint ERCOFTAC (SIG-15)/IAHR/QNET-CFDWorkshop
on Refined Turbulence Modelling", Poitiers, 2000.
Menter F.R. and Kuntz M., "Development and application of a zonal DES turbulence model
for CFX-5",CFX Internal Rep., Otterfing, Germany, 2003.
Minguez M., Pasquetti R. and Serre E., “Spectral vanishing viscosity stabilized LES of the
Ahmed body turbulent wake”, ICOSAHOM 07 Congress, Beijing, 2007, and Commun. in
Comput. Phys., vol.5, n°2-4, 635-648, 2008.
Minguez M., Pasquetti R. and Serre E., "High-order Large-Eddy Simulation of flow over the
“Ahmed body” car model", Phys. of Fluids, vol. 20, n°9, 095101-095101-17, 2008.
Pasquetti R. (a), "Spectral vanishing viscosity method for large-eddy simulation of turbulent
flows", ICOSAHOM 04 Congress, Brown university, 2004, and J. Sci. Comp., vol.27 (1-3),
, 2006.
Pasquetti R. (b), "Spectral vanishing viscosity method for high-order LES : Computation of
the dissipation rates", ECCOMAS CFD congress, P. Wesseling, J. Onate, J. Périaux (Eds),
Delft The Netherland 2006.
Pasquetti R., Bwemba R. and Cousin L., "A pseudo-penalization method for high Reynolds
number unsteady flows", Applied Numerical Mathematics, vol.58 (7), 946-954, 2008.
Piomelli U. and Balaras E., "Wall-layer models for large-eddy simulations", Annu. Rev. Fluid
Mech., 34, 349-374, 2002.
Sabbah C. and Pasquetti R., "A divergence-free multidomain spectral solver of the Navier-
Stokes equations in geometries of high aspect ratio", Comput. Phys., vol.139, 359, 1998.
Severac E., Poncet S., Serre E. and Chauve M.P., "Large eddy simulation and measurements
of turbulent enclosed rotor-stator flows", Phys. Fluids vol.19, 085113, 2007.
Spohn A. and Gillieron P., "Flow separations generated by a simplified geometry of an automotive
vehicle", In Proc. of IUATM symp on unsteady separated flows, Toulouse, 2002.
Tadmor E., "Convergence of spectral methods for non linear conservation laws", SIAM J.
Numer. Anal., vol. 26(1),30, 1989.
Tennekes H. and Lumley J., "A first course in Turbulence", The MIT Press, 1972.
