Dynamics of Taylor bubble interface in vertical turbulent counter-current flow

• DOI: 10.1016/j.ijmultiphaseflow.2023.104482
• Publication Date: 2023-04-12T15:20:46Z
• Authors: Jan Kren; Boštjan Zajec; Iztok Tiselj; Samir El Shawish; Žiga Perne; Matej Tekavčič; Blaž Mikuž
• Keywords: Taylor microscale; Neutral buoyancy

Dynamics of the Taylor bubble interface in vertical counter-current flow was analyzed with video recordings at 100 – 800 frames per second. bubbles air-water mixture were studied on time intervals up to several minutes stagnant conditions, where buoyancy is dynamically balanced by inertial drag downward turbulent flow. length from 4 10 cm observed a pipe 26 mm diameter Reynolds numbers based liquid superficial velocity around 6000. Algorithms, developed for analysis dedicated cap and body bubble. The long averaging min samples do not end axisymmetric time-averaged shape bubble, but an asymmetric bullet-train shape, thinnest film belly main result this study high relative sensitivity our measurements, which sufficient track dynamics tiny disturbance waves tenth amplitudes traveling along Cross-correlations time-dependent fluctuations measured different spatial positions allowed us measure propagation speeds waves. When averaged over sufficiently minute, velocities are shown be equal convective interface. Moreover, propagating both sides two-dimensional photographs show clear correlation; crest wave one side photograph corresponds trough other side.