This dataset combines multiple measurements form air-water horizontal annular flow experiments in a pipe (case A) and a pipe with circular orifice with ({d^2 / D^2} = 0.6)  (case B). Measurements where taken at superficial Reynolds numbers of Re=25000 for the gas phase and Re =4090 for the liquid phase. The following data are included for each case:

linear pressure drop between two points (case A), four points (case B) measured with split-range differential pressure transducers at 5Hz
time-averaged local liquid volume fraction distribution in cylindrical and Cartesian coordinates reconstructed from X-ray microtomography projections
reconstructed pipe axis coordinates and pipe radius
Python code to calculate secondary validation parameters (e.g. film thickness distribution) from primary data

The detailed 3D data is intended for validation of computational fluid dynamics codes based on phase-averaged variables such as the Euler-Euler approach.