A COMPUTATIONAL STUDY OF AEROFOIL MANIPULATORS IN LAMINAR AND TURBULENT-FLOW

A numerical investigation dealing with the influence of an aerofoil: m anipulator within a turbulent or laminar boundary layer is presented. The first part of the study concerns the Validation of the numerical c ode based on the finite volume method. It is demonstrated that computa tions are in good agreement with available experimental results, and v ery limited previous numerical results, for single aerofoil manipulato rs. Parametric turbulent flow calculations predict the correct variati on in device performance, in terms of resulting skin friction reductio ns, with the height and thickness of the manipulator. Computations for tandem configurations also correctly predict the improvement in skin friction reduction over that produced by a single device and the manne r in which this varies with tandem spacing. Similar trends are predict ed for laminar flow conditions, which have yet to be studied experimen tally, and there is evidence to suggest that the devices work best in turbulent flow if laminar flow is maintained in their wakes. Subsequen t studies of the effect of manipulator profile on performance have rev ealed that larger benefits can be obtained from asymmetric devices, pa rticularly at flight representative Mach numbers. Indeed it would appe ar that an inverted flattopped profile may offer the greatest skin-fri ction reductions in flight conditions.