TY - GEN

T1 - Dynamics and heat transfer in rotating horizontal convection at large Rayleigh number

AU - Vreugdenhil, C. A.

AU - Gayen, B.

AU - Griffiths, R. W.

N1 - Publisher Copyright:
© 2006 Australasian Fluid Mechanics Society. All rights reserved.

PY - 2016

Y1 - 2016

N2 - We examine the circulation forced by a gradient in surface temperature, known as horizontal convection, in a rectangular basin under planetary rotation. Direct numerical simulations are carried out to examine the problem in a closed rectangular basin that is heated over half of the base and cooled over the other half. Three Rayleigh numbers are considered, Ra = 7.4 ×108, 7.4 ×1011 and 7.4 ×1012, and Coriolis parameter is varied to give Ekman numbers in the range E = 6.4×10−8 −1.6×10−5. Other governing parameters are the Prandtl number Pr = 5 and vertical-to-length and horizontal-to-length aspect ratios, A = 0.16 and C = 0.24 respectively. The influence of rotation on flow dynamics and heat transfer depends on the natural Rossby number Ro = U/fL = (E/Pr)(RaE)2/3 where U is the flow velocity in the thermal boundary layer that forms adjacent to the forced surface and f is the Coriolis parameter. When the system is in a rapidly rotation regime (Ro < 0.1) the flow is characterised by geostrophic balance in the thermal boundary layer. The heat transfer, expressed as a Nusselt number, decreases with rotation but increases with buoyancy forcing as Nu ~ (RaE)1/3. A range of length scales are present in the rotating system that are associated with structures such as domain-scale gyres and full-depth convective vortices.

AB - We examine the circulation forced by a gradient in surface temperature, known as horizontal convection, in a rectangular basin under planetary rotation. Direct numerical simulations are carried out to examine the problem in a closed rectangular basin that is heated over half of the base and cooled over the other half. Three Rayleigh numbers are considered, Ra = 7.4 ×108, 7.4 ×1011 and 7.4 ×1012, and Coriolis parameter is varied to give Ekman numbers in the range E = 6.4×10−8 −1.6×10−5. Other governing parameters are the Prandtl number Pr = 5 and vertical-to-length and horizontal-to-length aspect ratios, A = 0.16 and C = 0.24 respectively. The influence of rotation on flow dynamics and heat transfer depends on the natural Rossby number Ro = U/fL = (E/Pr)(RaE)2/3 where U is the flow velocity in the thermal boundary layer that forms adjacent to the forced surface and f is the Coriolis parameter. When the system is in a rapidly rotation regime (Ro < 0.1) the flow is characterised by geostrophic balance in the thermal boundary layer. The heat transfer, expressed as a Nusselt number, decreases with rotation but increases with buoyancy forcing as Nu ~ (RaE)1/3. A range of length scales are present in the rotating system that are associated with structures such as domain-scale gyres and full-depth convective vortices.

UR - http://www.scopus.com/inward/record.url?scp=85084017656&partnerID=8YFLogxK

M3 - Conference contribution

T3 - Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2016

BT - Proceedings of the 20th Australasian Fluid Mechanics Conference, AFMC 2006

PB - Australasian Fluid Mechanics Society

T2 - 20th Australasian Fluid Mechanics Conference, AFMC 2006

Y2 - 5 December 2016 through 8 December 2016

ER -