A spreading drop in an interior corner: Theory and experiment

A liquid drop spreading spontaneously along interior corner is investigated theoretically and experimentally. The results are expected to be of value to designers of capillarity-controlled fluid systems. A similarity solution is presented from which the 3-dimensional dynamic interface may be described explicitly in terms of the interior corner angle and fluid properties, including the contact angle. The parametric range within which the solution is valid is provided inclusive of the effects of inertia, gravity, and the moving contact line boundary condition. Data from experiments employing laboratory and low-gravity environments, the latter aboard a DC-9 aircraft, are presented displaying the temporal (t) effects of fluid viscosity (μ), corner half-angle (α), and drop volume (H³) on the advancing tip location (ℒ) of the spreading drop. Theory and experiment compare well and reveal that ℒ ∼ (t²H²/μ²)^1/5.