Jet spreading and Jet inclination induced through complex vent geometry

This dataset provides data from 36 rapid decompression experiments performed in the Fragmentation Lab at Ludwig-Maximilians-Universität München (LMU, Munich, Germany) supporting the publication Schmid, M, Kueppers U, Cigala V, Sesterhenn J and Dingwell DB (202x) “Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards”. The experiments were aimed to constrain the influence of complex vent geometry on the instantaneous gas expansion in a shock-tube setup, mimicking impulsive volcanic explosions. They were performed at the following experimental conditions: 1) six vent geometries (conduit geometry always cylindrical), composed by 2 sets of inner geometry (cylindrical and 15° diverging) with inclined exit planes of 5, 15 or 30° slant angle, 2) constant temperature (25°C), 3) four starting overpressure scenarios (5, 8, 15, 25 MPa), and 4) two reservoir volumes (127.4 cm3, 31.9 cm3), achieved via variable conduit length, with Argon being used for the pressurization. During the experiments the setup is incrementally pressurized. When the desired experimental pressure in the reservoir is reached, rapid decompression is triggered (Kueppers et al., 2006; Cigala et al., 2017), producing a starting jet of expanding gas. Expansion-induced cooling leads to condensation of the Argon jet, allowing for optical analysis of gas expansion dynamics using highspeed videos. Gas dynamics (jet spreading and jet inclination) were analysed and correlated to experimental variables.