Direct numerical simulations are used to investigate the method of film cooling in a laminar flat-plate Mach-2.67 boundary layer. Air is employed as mean-flow and coolant gas and is introduced into the boundary layer through one row of holes by means of a modeled blowing approach. The effects of a favorable streamwise pressure gradient are investigated for two different blowing rates and an adi...

Unsteady wake-blade interaction is an inevitable consequence of the relative motion between rotors and stators in turbomachines. The flow in a low-pressure stage has a relatively low Reynolds number, of order 10 5 , based on chord length, and a substantial proportion of the boundary layer on the blade surface is thus laminar or transitional. While the flow in a turbine accelerates, globally, th...

The incompressible boundary layer in the axial flow past a cylinder has been shown Tutty et. al.([11]) to be stabler than a two-dimensional boundary layer, with the helical mode being the least stable. In this paper the secondary instability of this flow is studied. The laminar flow is shown here to be always stable at high transverse curvatures to secondary disturbances, which, together with a...

Laminar-turbulent transition in a 3-D boundary layer under controlled simultaneous forcing of unstable steady and unsteady crossflow waves is investigated by means of direct numerical simulations. The flow configuration reproduces the accelerated 3-D flat-plate boundary layer of the ”Querstr ömungsprinzipexperiment”of the DLRG öttingen [1]. The superposition of high-amplitude steady and unstead...