In this paper we investigate the formation of slug flow in horizontal pipes. We found that a slug is characterized by the memory of the turbulent stresses that formed it. However, the history of other turbulent fluctuations downstream the pipe is destroyed by passing slugs, preventing the formation of new slugs during and after their passage. As a result, the frequency of slug formation downstream the pipe is reduced. A probabilistic model is provided by making use of integral scales of turbulence in pipe flow and probabilistic effects of the properties of slug formation along the pipe. The model can act as a fundamental scientific guideline towards the design of gas-liquid horizontal pipe flow.
Predictions by the model were compared with slug frequency measurements found in literature. The agreement between the predictions and the measurements supports the idea that the turbulent fluctuations at the interface are responsible for the formation of slugs.
