Effect of water temperature on air-core generation and disappearance during draining

Understanding the air-core development during the draining of liquid from a cylindrical tank is of particular interest because this phenomenon has multiple engineering applications. In this study, experiments are performed for draining water of different temperatures from a cylindrical tank. Results show that the air-core generation and disappearance during draining depend on the temperature of the water in the tank, in which the total draining time increases with the water temperature. A correlation is proposed to predict the water height with time during draining. A numerical study is then performed for some of the temperature cases. Numerical and correlation results show a good agreement with the experimental data. Findings show that viscosity plays an important role behind the mechanism of air-core generation and disappearance phenomena.