Abstract An unsteady local heat transfer in an air synthetic non-steady-state jet impingement onto a flat plate with variation of the Reynolds number, nozzle-to-plate distance and pulses frequency is experimentally numerically studied. Measurements averaged pulsating at stagnation point are conducted using flux sensor. The axisymmetric URANS method stress model used for numerical simulations. F...

Oxygen gas-liquid mass transfer coefficient was measured in a gas-induced pulsating flow bubble column. Pulsating amplitude had a great influence on kla under pulsating state of equal base flow and pulsating flow, which was enhanced up to 30 % compared with that under steady state; however, it had a negative effect on mass transfer under a fixed low base flow. It was also found that kla had a n...

In this paper, we prove the uniqueness, up to shifts, of pulsating traveling fronts for reaction-diffusion equations in periodic media with Kolmogorov-Petrovsky-Piskunov type nonlinearities. These results provide in particular a complete classification of all KPP pulsating fronts. Furthermore, in the more general case of monostable nonlinearities, we also derive several global stability propert...

The intention of the present study is the detailed analysis of the unsteady vortex dynamics downstream the human glottis during phonation at typical fundamental frequencies of about 120 Hz (for men). A hydraulic respiratory mock circuit has been built-up including a three-times up-scaled realistic dynamic model of the vocal folds. Time-resolving flow measurements were carried out downstream the...

Motivated by recent event studies and modeling efforts on pulsating aurora, which conclude that the precipitation energy during these events is high enough to cause significant chemical changes in the mesosphere, this study looks for the bulk behavior of auroral pulsations. Based on about 400 pulsating aurora events, we outline the typical duration, geomagnetic conditions, and change in the pea...

The vorticity dynamics in the near field of laminar (Re = 10) co-flowing jets subjected to the single or combined effeets of axial and azimuthal forcing is analyzed. It is shown that the interaction of the three-dimensional vortex structure resulting from the growth of the two and three-dimensional instabilities may result in large changes in the entrainment and mixing characteristics of the je...