Shapes and stability of pendant and sessile dielectric drops in an electric field

摘要: Axisymmetric equilibrium shapes and stability of linearly polarizable dielectric (ferrofluid) drops fixed volume which are pendant/sessile on one plate a parallelplate capacitor subjected to an applied electric (magnetic) field determined by solving simultaneously the free boundary problem comprised Young-Laplace equation for drop shape Laplace distribution. When contact angle that makes with is be 90" distance between plates infinite, results identical those immersed in uniform resolve discrepancies previously reported theoretical predictions experimental measurements. Remarkably, regardless value ratio permittivity (permeability) surrounding fluid, K, develop conical tips as deformation increases. However, three types behaviour found, depending K. K K~ > K~, families become unstable at turning points respect strength. Beyond points, terminate : mean curvature virtually tip grows without bound. range < new predict exhibits hysteresis, accord experiments Bacri, Salin & Massart (1982) Bacri (1982, 1983). Such hysteresis phenomena have been surmized basis approximate theories, though they not calculated systematically until now. Moreover, detailed computations reveal importance varying size spacing, whether, along three-phase line, line or prescribed.