Rahul Kumar Mondal
School of Engineering, Indian Institute of Technology Mandi, Kamand-175075, Himachal Pradesh, India
Department of Mechanical and Industrial Engineering Indian Institute of Technology Roorkee, 247667, India; School of Engineering, Indian Institute of Technology Mandi, Mandi, Himachal Pradesh-175075, India
The present study has investigated the genesis of vortex structure within the tank and subsequent air entrainment into drainpipe when the liquid drains from multiple outlets of a tank. The liquid drainage rate from multiple outlets with two different pitches (P = 5d and P = 1.5d) have been compared to that of a single outlet drain rate. The drain rate in individual pipes of multiple outlets has been found nearly the same for different pitch variations. Generation of two individual plughole vortices for two tank outlets with pitch of 5d have been observed whereas the formation of two interacting plughole vortices originated from a single surface dip is obtained for multiple outlets having pitch of 1.5d. Critical pitch, at which vortex shape transformed from unified structure to two vortices, has been identified at P = 2d for two outlets having same drainpipe diameter (d). Evolution of surface dip and drainage rate has also been studied for multiple outlets having P = 5d, when diameter ratio (D/d) is varied. The ratio of rate of change of interface height (UD/Ud) has linearly increased upon increase of D/d due to variations in the shape of two vortices.