Authors: (Dirk Langemann, Univ. of Lubeck, Institute of Mathematics, Lubeck, Germany)
Abstract: The interest in droplets in electric fields results from the negative effects they produce on high-voltage outdoor equipment. Droplets and water films influence the aging behavior of insulator material which loses its hydrophobic and insulating properties. Mathematical models describing the coupled electro-mechanical phenomena lead to free boundary-value problems of the capillary surfaces in the stationary or in the quasi-stationary case and to hydrodynamical questions in fully time-dependent descriptions. The stationary case is solved with an iterative numerical method basing on pseudo-transient processes. At each time step, transition problems occur which are handled by finite elements or boundary elements. After an estimation of inertial and frictional effects, quasi-stationary models allow the simulation of moving droplets. In realistic set-ups, moving droplets leave water films which provoke undesired currents and even flashovers.