Effect of Non-isothermal Phase Change on Multiple Bubble Pulsations

• Published in: International journal of aeronautical and space sciences Vol. 24; no. 4; pp. 1063 - 1076
• Main Authors: Kim, Seonghak, Choi, Kyungjun, Kim, Chongam
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Society for Aeronautical & Space Sciences (KSAS) 01.09.2023; 한국항공우주학회
• Subjects: Aerospace Technology and Astronautics; Engineering; Fluid- and Aerodynamics; Original Paper; 항공우주공학; Bubble dynamics; Thermal effect; Compressible multiphase flow; Phase change effect; Multiple pulsations
• ISSN: 2093-274X; 2093-2480
• DOI: 10.1007/s42405-023-00581-9

Main reasons for the damage to submerged structures include shock waves and high-velocity jetting hits at the collapse of the cavitation bubbles, which repeatedly occur in subsequent bubble periods. Although other methods, e.g., experiments and theoretical approaches, have been conducted to gain knowledge of bubble dynamics, these approaches have difficulty in capturing microscopic phase changes and are not suitable for largely deforming motion, respectively. Therefore, numerical simulations using Navier–Stokes equations or Euler equations have been used to describe the bubble’s dynamic behaviors and detailed physical phenomena inside the bubble. Nevertheless, previous numerical simulations had limitations in expressing realistic and accurate bubble dynamics. For example, their results focused only on the first bubble period, not on multiple periods; thus, they could not obtain the information about the continuous shock loading near the structures. More noticeably, the thermal effect in multiple pulsations has never been addressed; since the pressure and temperature inside the bubble are formed near the critical point, the thermal effect has to be considered for accurate computations. Herein, the isothermal and non-isothermal phase change models are applied to observe the phase change effect and thermal effect on the bubble dynamics, respectively. Contrary to the isothermal model, which captures bubble dynamics up to the second bubble period, the non-isothermal model accurately expresses bubble dynamics up to the third bubble period, which is closely related to the thermal effect at the collapse region.