### Abstract

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 |

### Fingerprint

### Keywords

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

### Cite this

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

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**Oscillatory motion of liquid metals in non-isothermal geometries with converging or diverging walls.** / Ferialdi, Hermes; Lappa, Marcello.

Research output: Contribution to conference › Abstract

TY - CONF

T1 - Oscillatory motion of liquid metals in non-isothermal geometries with converging or diverging walls

AU - Ferialdi, Hermes

AU - Lappa, Marcello

N1 - Published in the 30th Scottish Fluid Mechanics Meeting Book of Abstracts, University of Strathclyde, Glasgow. ISBN 978-1-5272-0972-5.

PY - 2017/5/19

Y1 - 2017/5/19

N2 - 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.

AB - 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.

KW - thermogravitational flows

KW - fluid mechanics

KW - liquid metals

KW - buoyancy flow

KW - hydrodynamic instability

KW - CFD

M3 - Abstract

ER -