Engineering and Technology Journal

The aim of the present work is to study the virtual mass (added mass) coefficients for spherical-cap bubbles were measured by using five different spherical-cap sizes made of steel. The bodies were suspended by a fine wire over an aluminum pulley to weights which provided the driving force. The time taken for the spherical-cap bodies to moving through different distances were measured with a stop-watch. The force balance of accelerated motion for spherical-cap bodies is investigated and added mass coefficient is measured. The added mass coefficient for spherical-cap bodies a simulation of spherical-cap bubbles with different wake angle (50,60.5,75,90,120) degree is (19.76,8.86,4.08,2.69,1.26) respectively. The experimental results are compared with the theoretical results from some investigators.

The aim of the present work is to study the hydrodynamics of sphericalcap
bubble, rise bubble velocity, shape of bubble, and drag coefficient. The
experimental work of two-phase ,air-water system was carried out using a Perspex
column of 14.5 cm diameter and 180 cm height. A known volume of air was
supplied to the cup from a syringe. The single gas bubble rose through the
entrance region by turning the cup instantaneously. The rise bubble velocity was
measured by visual observation. In order to measure the terminal velocity an
electronic timer (Stop-Watch) was used. The drag coefficient of air spherica–l cap
bubble rising in water was measured and found to be a value between (2.8-3.8) for
all Reynolds number. The experimental results are compared with the theoretical
results of some investigators.