Numerical simulation of fully-developed compressible flows over wavy surfaces

Tyson, c.j. and Sandham, N. D. (2013) Numerical simulation of fully-developed compressible flows over wavy surfaces. International Journal of Heat and Fluid Flow, 41, 2-15. (doi:10.1016/j.ijheatfluidflow.2013.02.006).

Record type: Article

Abstract

Rough surfaces are common on high-speed vehicles, for example on heat shields, but compressibility is
not usually taken into account in the flow modelling other than through the mean density. In the present
study, supersonic fully-developed turbulent rough wall channel flows are simulated using direct numerical
simulation to investigate whether strong compressibility effects significantly alter the mean flow and
turbulence properties across the channel. The simulations were run for three different Mach numbers
M = 0.3, 1.5 and 3.0 over a range of wall amplitude-to-wavelength ratios from 0.01 to 0.08, corresponding
to transitionally and fully rough cases respectively. The velocity deficit values are found to decrease with
increasing Mach number. It is also found that at Mach 3.0 significant differences occur in the mean flow
and turbulence statistics throughout the channel and not just in a roughness sublayer. These differences
are found to be due to the presence of strong shock waves created by the peaks of the roughness
elements.