Gravitational modes of convection in water liquid bridges

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
16 Downloads (Pure)

Abstract

The modes of pure buoyant (thermogravitational) convection emerging in a liquid bridge of water (Pr=6.1), uniformly heated from below and cooled from above are investigated experimentally by means of a microscale facility, a related laser-cut technique (used to illuminate isodense tracers dispersed in the liquid) and a PIV (Particle Image Velocimetry) method. In particular, the following conditions are examined: aspect ratio (A=length/diameter) in the range 0.3≤A≤0.9, volume ratio 0.7≤S≤1.3 and Rayleigh number spanning the interval from the initial quiescent state up to the development of oscillatory motion. A multitude of patterns is obtained revealing the coexistence of different branches of steady flows in the space of parameters in the form of multiple solutions. These can evolve into oscillatory states featured by disturbances with the characteristics of standing waves (a kind of rocking motion). The analysis largely relies on a novel approach where the position of the center of the main vortex of buoyant nature established in the liquid bridge is carefully monitored in space. The related trajectory is used to discern the flow spatial degrees of freedom, which are progressively enabled as the temperature difference is increased. It is shown that the effective volume of liquid held by surface tension between the hot and cold walls can have an appreciable impact on the onset of unsteadiness and the related oscillation frequency.
Original languageEnglish
Article number054113
Number of pages23
JournalPhysics of Fluids
Volume36
DOIs
Publication statusPublished - 15 May 2024

Keywords

  • buoyancy convection
  • liquid bridge
  • pattern selection
  • flow instability
  • volume effect

Fingerprint

Dive into the research topics of 'Gravitational modes of convection in water liquid bridges'. Together they form a unique fingerprint.

Cite this