Abstract
As a basis of designing unlined caverns for storage of liquid petroleum gas, terminal rising velocities VT and drag coefficient CD of single bubbles in a stagnant liquid filling in narrow parallel walls were measured in the present study using air and water at atmospheric pressure and room temperature. The gap width dδ of the parallel walls was varied from 300μm to 900μm. The bubble diameter de was from 1mm to 20mm. It was confirmed that VT was affected by δ as well as de. In addition, rising motion of a bubble was found to be classified into two states: one is the state of low VT when de is small and the other is that of high VT when de is large. Transition between these states was observed when de was intermediate size. Empirical correlations of VT and CD for each state were developed by taking into acount forces acting on a bubble.
