ABSTRACT
We develop a lubrication approximation model, using the Herschel–Bulkley constitutive equation, with dimensionless flow parameters including the Bingham number, the power-law index, the buoyancy number, the viscosity ratio, the diameter ratio, the eccentricity and the aspect ratio. Based on a reasonable prediction to the yielding onset, the model allows us to classify the flow regimes versus an elegant combination of the dimensionless numbers. We study the injection flow of a heavy viscoplastic fiuid into a light Newtonian fiuid, via modelling and experiments. The injection is carried out downward, via an eccentric inner pipe inside a vertical closed-end outer pipe. This configuration results in a core viscoplastic fiuid surrounded by an annular Newtonian fiuid. The flow is structured and mixing is negligible. As the injection rate increases in a typical experiment, we observe three distinct flow regimes, associated with the core fiuid behavior, namely the breakup, coiling and buckling (bulging) regimes
ABSTRACT
Esophageal injury resulting from electrical shock is rare. Stricture of esophagus following external electrical injury has not been reported yet. We report a 24-year-old electric lineman who developed esophageal stricture following external electrical shock. He responded to dilatation with Savary-Gilliard dilators.