Lorenzo Siconolfi

Mixing performance of arrow-shaped micro-devices.

The process of liquid laminar mixing in arrow-shaped micro-devices is studied by direct numerical simulations. Two different CFD codes, i.e. Fluent (based on finite volume method) and Nek5000 (based on spectral element method) have been used to investigate the flow and concentration fields. Unexpectedly we observe that within the engulfment regime, the degree of mixing first increases and then diminishes as the inlet flow rate is increased. Such reduction in the degree of mixing, not observed in T-shaped mixers, can be imputed to the presence of a strong vortical structure at the center of the mixing channel. This result is important for control operations, as it shows that on one hand arrow type mixers are characterized by higher degree of mixing with respect to T-shaped mixers, but on the other hand they present a narrower range of optimal conditions.

Stability and Sensitivity Analysis of the Secondary Instability in the Sphere Wake

The three-dimensional flow past a fixed sphere placed within a uniform stream is investigated. This paper focuses on the second bifurcation, which is responsible for the onset of the unsteadiness. ...

Uncertainty Quantification in Large-Eddy Simulations of the Flow Around a 5:1 Rectangular Cylinder

The Benchmark on the Aerodynamics of a Rectangular Cylinder (BARC) with chord-to-depth ratio equal to 5, sketched in Fig. 1a, was launched in 2008 with the aim of collecting a large number of flow realizations obtained both in wind tunnels and in numerical simulations.