Numerical simulation, validation, and analysis of two-phase slug flow in large horizontal pipes

Multiphase flow, especially two-phase gas-liquid flow, is of great importance for a variety of applications and industrial processes, for example in the nuclear, chemical, or oil and gas industries. In this contribution, we present simulation results for gas-liquid slug flow in large horizontal pipes. Six test cases with different oil, water, and gas flow rates are considered, which cover a wide range of different slug flows. The numerical predictions are validated by comparison with experimental data obtained from video observations. The relative error of the mean liquid level between experiment and simulation is less than 12.3% for all but one test cases. Furthermore, a frequency analysis is performed. The single-sided amplitude spectrum as well as the smoothed power spectral density are calculated. For both, experimental and simulation data, one observes an increase of the dominant frequencies if the ratio of liquid and gas superficial velocity is increased.