TY - JOUR
T1 - Single sidewall cooling modulation on Rayleigh-Bénard convection
AU - Kang, Soohyeon
AU - Cheng, Shyuan
AU - Hong, Liu
AU - Kim, Jin Tae
AU - Chamorro, Leonardo P.
N1 - Publisher Copyright:
© The Author(s), 2023. Published by Cambridge University Press.
PY - 2023/2/25
Y1 - 2023/2/25
N2 - We experimentally explored the effect of single-sidewall cooling on Rayleigh-Bénard (RB) convection. Canonical RB was also studied to aid insight. The scenarios shared tank dimensions and bottom and top wall temperatures; the single sidewall cooling had the top wall temperature. Turbulence was explored at two canonical Rayleigh numbers, and under Prandtl number. Particle image velocimetry described vertical planes parallel and perpendicular to the sidewall cooling. The two scenarios reveal pronounced changes in the flow structure and large-scale circulation (LSC) due to the sidewall cooling. The density gradient induced by the sidewall cooling led to asymmetric descending and ascending flows and irregular LSC. Flow statistics departed from the canonical case, exhibiting lower buoyancy effects, represented by an effective Rayleigh number with effective height dependent on the distance from the lateral cooling. Velocity spectra show two scalings, Kolmogorov (KO41) and Bolgiano (BO59) in the larger; the latter was not present in the smaller set-up. The BO59 scaling with sidewall cooling appears at higher frequencies than its canonical counterpart, suggesting weaker buoyancy effects. The LSC core motions allowed us to identify a characteristic time scale of the order of vortex turnover time associated with distinct vortex modes. The velocity spectra of the vortex core oscillation along its principal axis showed a scaling of for the single sidewall cooling, which was dominant closer there. It did not occur in the canonical case, evidencing the modulation of LSC oscillation on the flow.
AB - We experimentally explored the effect of single-sidewall cooling on Rayleigh-Bénard (RB) convection. Canonical RB was also studied to aid insight. The scenarios shared tank dimensions and bottom and top wall temperatures; the single sidewall cooling had the top wall temperature. Turbulence was explored at two canonical Rayleigh numbers, and under Prandtl number. Particle image velocimetry described vertical planes parallel and perpendicular to the sidewall cooling. The two scenarios reveal pronounced changes in the flow structure and large-scale circulation (LSC) due to the sidewall cooling. The density gradient induced by the sidewall cooling led to asymmetric descending and ascending flows and irregular LSC. Flow statistics departed from the canonical case, exhibiting lower buoyancy effects, represented by an effective Rayleigh number with effective height dependent on the distance from the lateral cooling. Velocity spectra show two scalings, Kolmogorov (KO41) and Bolgiano (BO59) in the larger; the latter was not present in the smaller set-up. The BO59 scaling with sidewall cooling appears at higher frequencies than its canonical counterpart, suggesting weaker buoyancy effects. The LSC core motions allowed us to identify a characteristic time scale of the order of vortex turnover time associated with distinct vortex modes. The velocity spectra of the vortex core oscillation along its principal axis showed a scaling of for the single sidewall cooling, which was dominant closer there. It did not occur in the canonical case, evidencing the modulation of LSC oscillation on the flow.
KW - Bénard convection
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U2 - 10.1017/jfm.2022.1026
DO - 10.1017/jfm.2022.1026
M3 - Article
AN - SCOPUS:85148485636
SN - 0022-1120
VL - 957
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
M1 - A13
ER -