| dc.description |
The objective of the study is to investigate the capability of PANS (Partially
Averaged Navier -Stokes Simulation ) model over a wide range of Reynolds numbers and
flow physics . In this regard , numerical simulations of turbulent flow past a circular
cylinder are performed at ReD 140 ,000 and ReD 3900 using the PANS model . The high
Reynolds number PANS results are compared with experimental results from Cantwell
and Coles , Large Eddy Simulation results from Breuer , and Detached Eddy Simulation
results from Travin et al . Low Reynolds number PANS results are compared with
experimental results from Ong and Wallace and Large Eddy Simulation results from
Breuer . The effects of the various PANS parameters (fk , f & #949 ; , & #963 ;ku , & #963 ; & #949 ;u ) on the ability to
capture turbulence physics at various Reynolds numbers are studied . It is confirmed , as
previously predicted from theoretical considerations that : (i ) for high Reynolds number
flow f & #949 ; = 1 and & #963 ;ku = & #963 ;k à fk2 / f & #949 ; are most appropriate ; and (ii ) for low Reynolds number
flow f & #949 ; = fk and & #963 ;ku = & #963 ;k are most suitable . These choices for the parameters stem from
the fact that there is no clear separation of scales between the energy scales and the
dissipation scales at low Reynolds number unlike in the high Reynolds number where
there is a clear separation of scales between the energy containing scales and the
dissipation scales . Also , in both cases it is found that decreasing fk leads to improved
accuracy in predicting the flow statistics . |
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