English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We report an experimental study of the large-scale circulation (LSC) in aturbulent Rayleigh-B\'{e}nard convection cell with aspect ratio unity. Thetemperature-extremum-extraction (TEE) method for obtaining the dynamicinformation of the LSC is presented. With this method, the azimuthal angularpositions of the hot ascending and cold descending flows along the sidewall areidentified from the measured instantaneous azimuthal temperature profile. Themotion of the LSC is then decomposed into two different modes: the azimuthalmode and the translational or off-center mode. Comparing to the previoussinusoidal-fitting (SF) method, it is found that both methods give the sameinformation about the azimuthal motion of the LSC, but the TEE method inaddition can provide information about the off-center motion of the LSC, whichis found to oscillate time-periodically around the cell's central vertical axiswith an amplitude being nearly independent of the turbulent intensity. It isfurther found that the azimuthal angular positions of the hot ascending flownear the bottom plate and the cold descending flow near the top plate oscillateperiodically out of phase by $\pi$, leading to the torsional mode of the LSC.These oscillations are then propagated vertically along the sidewall by the hotascending and cold descending fluids. When they reach the mid-height plane, theazimuthal positions of the hottest and coldest fluids again oscillate out ofphase by $\pi$. It is this out-of-phase horizontal positional oscillation ofthe hottest and coldest fluids at the same horizontal plane that produces theoff-center oscillation of the LSC. A direct velocity measurement furtherconfirms the existence of the bulk off-center mode of the flow field near cellcenter.

journal of fluid mechanics

Oscillations of the large-scale circulation in turbulent  Rayleigh-B\'{e}nard convection: the off-center mode and its relationship with  the torsional mode