### Abstract

Thermogravitational flows of liquid metals are widespread in technology and related engineering
applications. We investigate the typical properties of these flows and associated hierarchy of
bifurcations in geometries with converging or diverging walls by solving the Navier Stokes and energy
equations in their time‐dependent and non‐linear formulation. It is shown that an increased variety of
oscillatory patterns and waveforms (with respect to classical purely rectangular cavities) is made
possible by the new degree of freedom represented by the opposite inclination of the walls with
respect to the horizontal direction. Even limited variations in the geometry and/or initial conditions
can cause significant changes. An increase (a decrease) in the geometrical expansion (or compression)
ratio from the condition 1determines a reduction of the number of rolls, whereas an increase
in the Rayleigh number is generally responsible for an increase in the wavenumber m, the angular
frequency and the complexity of the frequency spectrum (with the possible coexistence in some
circumstances of disturbances operating at different time and spatial scales). The most interesting
information provided by our numerical results, however, is the evidence they give about the
existence of “multiple states”, which can replace each other in given sub‐regions of the space of
parameters. Observed regimes include: quasi‐stationary convection, weakly oscillating rolls,
coalescing rolls, traveling waves, and modulated (pulso‐traveling) disturbances.

Original language | English |
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Number of pages | 1 |

Publication status | Published - 19 May 2017 |

Event | 30th Scottish Fluid Mechanics Meeting - University of Strathclyde, Glasgow, United Kingdom Duration: 19 May 2017 → 19 May 2017 |

### Conference

Conference | 30th Scottish Fluid Mechanics Meeting |
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Country | United Kingdom |

City | Glasgow |

Period | 19/05/17 → 19/05/17 |

### Keywords

- thermogravitational flows
- fluid mechanics
- liquid metals
- buoyancy flow
- hydrodynamic instability
- CFD

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## Cite this

Ferialdi, H., & Lappa, M. (2017).

*Oscillatory motion of liquid metals in non-isothermal geometries with converging or diverging walls*. Abstract from 30th Scottish Fluid Mechanics Meeting, Glasgow, United Kingdom.