The evolution of a viscous gravity current in a confined geometry

We describe a theoretical and experimental study of an axisymmetric viscous gravity current with constant flux, confined to the space between two horizontal parallel plates. The effect confinement results in regions flow: inner region where fluid is contact both plates outer annular forms along lower plate. present simple model that describes flow dynamics by single dimensionless parameter $J$ , which ratio characteristic height unconfined space. Theoretical profiles display same characteristics as currents until $J \approx 0.48$ rapid change behaviour occurs comes into effect. For larger values gradually tends Hele-Shaw flow, transition essentially complete 2$ . compare findings from our series experiments using golden syrup various fluxes gap spacings. Although data aligns major aspects model, it clear other physics at play non-dimensional not sufficient capture fully. speculate on factors absent may be responsible for this mismatch.