Flow transitions in natural convection


Passive heat dissipation relying upon natural convection is employed in several engineering fields, including electronic, nuclear, and civil. As a matter of fact, buoyancy-induced flows offer remarkable advantages with respect to machine-driven ones, the main of which resides in being power supply free. The present project aims at investigating the case of a heated cylinder horizontally positioned inside an isothermal cavity. The configuration of a cylindrical heat source confined within an enclosure has recently aroused a growing interest, for two main reasons: firstly, many technological applications can be modeled in such a way, and secondly, the characterization of the phenomena governing the transition to chaos is simpler here than in other kind of buoyancy-induced flows. In particular, the flow transitions leading to chaos are shown to be repeatable, whereas in other convective systems (e.g., the Rayleigh-Bénard systems) these are strongly dependent on the initial conditions.


The goal of the project is to characterize the heat and mass transfer within the cavity, with a particular focus on the patterns of flow that the system exhibits across the different flow regimes. As a secondary objective, results will be compared with numerical predictions from a home-made code developed by the University of Modena and Reggio Emilia, to allow its validation. Measurement techniques will include: hot-wire anemometry, Particle Image Velocimetry (PIV), and thermocouples. An integral part of the project will be the design and the construction of an experimental set-up, where the leading parameter of the problem (i.e. the Rayleigh number) and the geometric configuration of the case under study (e.g., the position of the cylinder) can be varied.



  1. Bergé P., Pomeau Y., and Vidal C., Order within chaos. Towards a deterministic approach to turbulence. Editeurs des sciences et des arts, 1984.

  2. Labonia G., and Guj G., Natural convection in a horizontal concentric cylindrical annulus: oscillatory flow and transition to chaos, Journal of Fluid Mechanics 375 (1998) 179-202.

  3. Angeli D. et al., Routes to chaos in confined thermal convection arising from a cylindrical heat source, Chaotic modelling and simulation 1 (2011) 61-68.



Daniele Fiscaletti, d.fiscaletti@tudelft.nl


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