In many thermal convection studies, enclosure inclination against gravity (measured as $\mathrm{\Phi }$) changes both flow features and heat transport. We numerically investigated thermal convection in a quasi-two-dimensional circular enclosure in the range ${10}^7\le \text{Ra}\le {10}^{10}, 0.1\le \text{Pr}\le 15$, and $0\le \mathrm{\Phi }\le \pi /2$, where $\text{Ra}$ is the Rayleigh number and $\text{Pr}$ is the Prandtl number. The dimensionless heat transport follows a nonmonotonic trend due to the change in plume nature near the walls, elimination of secondary rolls, core bulk instabilities, and flow stratification. Our scaling analysis shows dimensionless heat transport is proportional to ${\left(\text{Ra}\text{cos}\mathrm{\Phi }\right)}^{1/3}$ at small $\mathrm{\Phi }(0\le \mathrm{\Phi }<\frac{\pi }{9})$ and to ${\left(\text{Ra}\text{sin}\mathrm{\Phi }\right)}^{1/4}$ at large $\mathrm{\Phi }(\frac{\pi }{9}\le \mathrm{\Phi }\le \frac{\pi }{2})$. In contrast, the Reynolds number based on the global root-mean-square velocity shows a continuous decrease with $\mathrm{\Phi }$ due to the reduction in buoyancy fluxes, which convert the available potential energy into kinetic energy. Though the buoyancy flux decreases, convection persists through irreversible mixing, which is the dominant mechanism in inclined thermal convection.

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• Convection
• Geophysical fluid dynamics
• Plumes & thermals
• Rayleigh-Bénard convection
• Thermal convection