During champagne cork popping, the CO2/H2O gas mixture initially under pressure in the bottleneck freely expands into ambient air and experiences adiabatic cooling. A comparison between the condensation phenomena accompanying cork popping from bottles stored at 20° and 30°C was made. The initial headspace-to-ambient-pressure ratio much exceeded the critical ratio needed for the gas mixture to reach Mach 1, thus forming under-expanded supersonic CO2 freezing jets expelled from the throat of the bottlenecks. It was emphasized that, after adiabatic cooling and with a saturation ratio for gas-phase CO2 about twice higher for the bottles stored at 30°C, dry ice CO2 clusters grow bigger and reach the critical size needed to achieve the Mie scattering of light. Moreover, during the very first millisecond following cork popping, evanescent normal shock waves (or Mach disks) were unveiled in the jets, until the reservoir-to-ambient-pressure ratio goes below a critical ratio.

https://advances.sciencemag.org/content/advances/5/9/eaav5528.full.pdf

Under-expanded supersonic CO2 freezing jets during champagne cork popping.

Supersonic jet and nozzle flows in uniform-flow and free-vortex aerodynamic windows of gas lasers

Experimental measurements of the spatial distribution of temperature and composition of ablation-controlled arc plasmas are a key to validate the predictions of metal evaporation and polymer ablati ...

https://iopscience.iop.org/article/10.1088/1361-6463/ab34b6/pdf

Temperature and pressure profiles of an ablation-controlled arc plasma in air

Influence of nozzle external geometry on wavepackets in under-expanded supersonic impinging jets

Supersonic jets are widely used in devices based on a self-oscillation process emerging during the interaction of a gas flow with tubular cavities (gas-jet acoustic emitters). We analyze the mechanisms for sustaining undamped pulsations of pressure and determine the flow field in a tubular cavity during the interaction of an underexpanded supersonic jet with it. We consider the physical pattern of the flow in the cavity of a gas-jet emitter, demonstrate the existence of odd longitudinal modes, and propose wave diagrams for describing the flow in odd longitudinal modes. Wave diagrams are constructed based on analysis of signals from piezoelectric sensors detecting pressure pulsations in a tubular cavity. The flow parameters in the tubular cavity in the longitudinal modes are calculated using the flow velocity–velocity of sound diagram.

Flow Structure and Pressure Oscillations during the Interaction of a Supersonic Underexpanded Gas Jet with a Tubular Cavity

In the present paper, we give a brief overview of the studies of supersonic jet flows which were performed recently with the aim of gaining experimental data on the formation of the shock-wave structure and jet mixing layer in such flows. Considerable attention is paid to a detailed description of discharge conditions for supersonic jets, to enable the use of measured data for making a comparison with numerical calculations. Data on the 3D flow structure in the mixing layer of the initial length of a supersonic jet are reported. Scientific interest in this phenomenon is due to its practical significance in studying the possibility of intensifying the mixing process as well as in studying the sound-generation process.

/pdf/shock-wave-structure-of-supersonic-jet-flows-3xj0up5vfg.pdf

Valery Zapryagaev

Papers

Shock-Wave Structure of Supersonic Jet Flows