Flows around missiles, rockets and projectiles often experience
baseflow separation. This means that the pressure
behind the base is considerably lower than the freestream
pressure, causing base drag that often constitutes a large
portion of the total drag. The present study is motivated by
the fact that most methods used for reducing the drag often
also reduce the aerodynamic stability of the vehicle. Semianalytical
methods and Reynolds Average Navier-Stokes
(RANS) models often fail to provide accurate results for
such flows, and therefore we use Large Eddy Simulations
(LES) to investigate the flow physics of axisymmetric
baseflow in a configuration for which experimental data is
available for comparison. Good agreement with experimental
data, with and without, base bleed is obtained for
several LES models, suggesting that the details of the subgrid
model are of less importance. The simulation data are
also examined with the intention of increasing our knowledge
of the underlying flow physics.
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