BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Effects triggered by singular solutions in the collapse of non-sph
 erical bubbles - Daniel Fuster\, Institut D'Alembert
DTSTART:20250213T113000Z
DTEND:20250213T123000Z
UID:TALK225982@talks.cam.ac.uk
CONTACT:Catherine Pearson
DESCRIPTION:The Rayleigh collapse problem is defined as the implosion of a
  cavity in a liquid at a higher ambient pressure and\nrepresents an ideali
 zed problem relevant in applications related to cavitation\, environmental
  science\, medical treatment and many others inertially driven collapse pr
 ocesses. In the simplest model the bubble is assumed to remain spherical d
 uring the entire collapse process leading to an extreme concentration of t
 he energy of the system. The solution of the bubble radius evolution for t
 he particular case of an empty void has a singularity at a finite time tha
 t provides the well-know\nRayleigh collapse time being possible to extend 
 the analysis to account for the presence of non-condensable gases\nand obt
 ain theoretical estimates about the finite peak pressures and temperatures
  that can be reached during the collapse process. \n\nIn this work we revi
 sit the analytical expressions for the singular collapse of bubbles to dis
 cuss the importance of non-spherical effects for a spherical cap bubble in
 itially in contact with a wall. We show that the solution of this problem 
 presents a singularity in the initial acceleration field at the triple con
 tact point  when the initial contact angle is larger than 90 degrees. The 
 appearance of this singularity clearly distinguishes two\ndifferent regime
 s of bubble-wall interactions. When the initial contact angle is smaller t
 han 90 degrees\, a classical jet resulting from the interaction with the w
 all is directed towards the wall  being responsible for the damage process
 es of the wall. Interestingly\, when the initial contact angle is larger t
 han 90 degrees\, the effects of the singularity present in the solution of
  the Euler equations\nbecome visible and a jet parallel to a wall develops
   leading to the formation of a vortex ring that propagates in the directi
 on opposite to the wall  and that can travel significant distances. Theore
 tical arguments are provided to interpret the numerical results obtained f
 rom the DNS of the\nNavier-Stokes equations and  experiments where we show
  that these effects are behind the long range interactions between a free 
 surface and  the collapse of a bubble at the bottom of a water filled tank
  (Saini et al\, JFM\, 2022). We also show that these non-spherical effects
  can lead to significant deviations on the scaling laws for the peak press
 ures and temperatures predicted by the spherically symmetric theory.
LOCATION:Open Plan Area\, Institute for Energy and Environmental Flows\, M
 adingley Rise CB3 0EZ
END:VEVENT
END:VCALENDAR