Temporal characteristics of the probability density function of velocity in wall-bounded turbulent flows

The probability density function (p.d.f.) of the streamwise velocity has been shown to indicate the presence of uniform momentum zones in wall-bounded turbulent flows. Most studies on the topic have focused on the instantaneous characteristics of this p.d.f. In this work, we show how the use of time-resolved particle image velocimetry data...

On Reynolds number dependence of micro-ramp-induced transition

The variation of transitional flow features past a micro-ramp is investigated when the Reynolds number is decreased approaching the critical regime. Experiments are conducted in the incompressible flow spanning from supercritical to subcritical roughness-height-based Reynolds number ( , 730, 460 and 320) with tomographic particle image...

Three-dimensional organisation of primary and secondary crossflow instability

An experimental investigation of primary and secondary crossflow instability developing in the boundary layer of a 45° swept wing at a chord Reynolds number of 2.17 × 10⁶ is presented. Linear stability theory is applied for preliminary estimation of the flow stability while surface flow visualisation using fluorescent oil is...

Turbulent structure of high-amplitude pressure peaks within the turbulent boundary layer

Counter-hairpin vortices in the turbulent wake of a sharp trailing edge