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

Combined measurements of velocity components and temperature in a turbulentRayleigh-B\'enard convection flow at a low Prandtl number of $\mathit{Pr}=0.029$ and Rayleigh numbers between $10^6 \le \mathit{Ra} \le 6 \times 10^7$are conducted in a series of experiments with durations of more than a thousandfree-fall time units. Multiple crossing ultrasound beam lines and an array ofthermocouples at mid-height allow for a detailed analysis and characterizationof the complex three-dimensional dynamics of the single large-scale circulation(LSC) roll in the cylindrical convection cell of unit aspect ratio which isfilled with the liquid metal alloy GaInSn. We measure the internal temporalcorrelations of the complex large-scale flow and distinguish between short-termoscillations associated with a sloshing motion in the mid-plane as well asvarying orientation angles of the velocity close to the top/bottom plates andthe slow azimuthal drift of the mean orientation of the roll as a whole thatproceeds on an up to a hundred times slower time scale. The coherent LSC drivesa vigorous turbulence in the whole cell that is quantified by direct Reynoldsnumber measurements at different locations in the cell. The velocity incrementstatistics in the bulk of the cell displays characteristic properties ofintermittent small-scale fluid turbulence. We also show that the impact of thesymmetry-breaking large-scale flow persists to small-scale velocityfluctuations thus preventing the establishment of fully isotropic turbulence inthe cell centre. Reynolds number amplitudes depend sensitively on beam lineposition in the cell such that different definitions have to be compared. Theglobal momentum and heat transfer scalings with Rayleigh number are found toagree with those of direct numerical simulations and other laboratoryexperiments.

Combined measurement of velocity and temperature in liquid metal convection