The present experimental investigation is focused on the influence of gravity upon water-droplet formation in a Y-microchannel filled with oil. The flows are in the Stokes regime, with very small capillary numbers and Ohnesorge numbers less than one. The study was performed in a square-cross-section channel, with a = 1.0 mm as the characteristic dimension and a flow rate ratio $\kappa$ in a range between 0.55 and 1.8. The interface dynamics in the vicinity of breakup and the transitory plug flow regime after the detachment of the droplet were analysed. The dependence of droplet length L was correlated with the channel position against the gravity and $\kappa$ parameters. The results of the work prove that, for $\kappa =1$, the droplet length L is independent of channel orientation.

The paper is dedicated to the experimental and numerical investigations of the flow around cylinders inside a microchannel with cross section 500×100 μm. The study analyses the influence of Reynolds number on the flow spectrum downstream the cylinders. Qualitative and quantitative visualizations of the flow and the velocity distributions using µPIV technique are obtained around one cylinder. The numerics performed with the ANSYS Fluent code for the cylinder diameter 200 µm are validated by the experiments. The flow patterns and the vortices downstream one cylinder and 3 cylinders (positioning transversally and longitudinally on the flow direction) are numerically investigated.

The paper is concerned with experimental studies and numerical modelling of the air flow around blunt bodies (cylinder, aerodynamic profile) inside a wind tunnel. The range of the investigated Reynolds numbers is 12000<Re<35000. The main goal of the work is to establish a CFD procedure to analyse the flow pattern in the vicinity of the bodies and to predict the position of the boundary layer detachment. The computations are performed with several turbulence models implemented in the ANSYS Fluent code. The direct visualizations and the numerical results are corroborated, with the aim to investigate the positions of the separation points and the flow spectrum developed downstream the bodies.