Fig. 1: Experimental setup.
From: Particulate reshapes surface jet dynamics induced by a cavitation bubble
a A sketch of the experimental setup. The spark bubble was generated by a low-voltage discharge method, and a surface defect was created by floating a sphere on the water surface. Two high-speed cameras were used to capture the evolution of the water surface and the underwater spark bubble, respectively. b A solid sphere with a radius of r creates a defect when floated on the water surface. The underwater spark bubble is at a distance h below the initial water line, with its instantaneous radius R(t). The photograph captures the moment (t = τ) as the bubble reaches its maximum radius Rm. The interaction causes an upward deformation of the water surface, forming a pit over the sphere. c Underwater close-up of three copper spheres (r = 500 μm) resting on still water with varying contact angles (θ = 81∘, 108∘, and 154∘). The red dotted lines outline their emerged parts above the water surface. The azimuthal angle of the contact line, ϕ, and the arc length of the unimmersed portion, s, are also indicated. All scale bars represent 1 mm.
