A sheet of light from an Argon ion laser will be used to visualize the gas-liquid two-phase flow in various geometries. Transparent plexiglass test sections of spherically convex, rectangular and convergent-divergent channels will be considered. The pressure drop fluctuations at the wall will be also measured. The power spectrum for the fluctuating interfacial area concentration will be determined. An attempt will be made to interpret the pressure and flow visualization measurements with a statistical model. This experimental study will provide new data on gas-liquid two-phase flow phenomena in channels, which may be used for modeling and instrumentation development.