Dynamics of a dry spot

Abstract

Experimental results are presented for the motion of a dry spot in a thin viscous film on a horizontal surface. These include global and spatial measurements of dry spot diameter, front velocities, static and dynamic contact angle, and the shape of the liquid–solid interface. Data are presented as a function of initial fluid depth for both an advancing fluid front of a collapsing dry spot and a receding fluid front of an opening dry spot. Results for both cases show that the final or static hole diameter increases as the initial fluid depth decreases. Also, insight is obtained into the relationship between the contact angle and the velocity for both advancing and receding fluid fronts. The experimental results are compared to a lubrication model, and good agreement is obtained.

Healing capillary films

“…In the work of Moriarty & Schwartz (1993), advancing and retreating contact angles were prescribed, and the contact line was moved artificially by a mesh point if the angle was greater or less than the advancing or retreating value, respectively (effectively a kind of numerical slip). The stability was also studied by López et al (2001), using the lubrication approximation together with a more natural Navier slip model (along with an assumed contact angle-velocity relation) to regularize the contact line singularity, instead of the numerical slip that Moriarty & Schwartz (1993) implemented, and the numerical results compared favourably to subsequent experimental work (Bankoff et al 2003).…”

Self-similar collapse of a circular cavity of a power-law liquid

“…The closure of a circular cavity when surface tension is relevant has been studied in [14][15][16], and in the inertia dominated regime in [17,18]. In both these problems a self-similar regime develops close to the centre and the instant of collapse.…”

Dynamic wetting of an occlusion after droplet impact

“…Hole formation in a thin sheet of liquid has fascinated many researchers in recent decades (Paddy, 1970;Taylor and Michael, 1973;Redon et al, 1991;Kheshgi and Scriven, 1991;Moriarty and Schwartz, 1993;Lopez et al, 2001;Bankoff et al, 2003 andSellier et al, 2015).…”