Electrical corona discharges at atmospheric pressure in a positive point-to-plane configuration create an electric wind from the point to the plane which, in a closed cylindrical vessel, generates in a few seconds axisymmetrical vortices in the vessel. Photography and video recording show that a small ring vortex appears around the discharge axis, close to the plane, enlarges and progressively fills the vessel up to a stationary situation. A simplified stationary model was first used in order to take into account the measured values of the wind velocity along the discharge axis as well as the velocity field lines visualized by smoke particles. Simulation and experimental results are in fairly good agreement, and a few particular adjustments concerning temperature profiles were made to improve the numerical results. Then, a dynamical model, including the effect of the repetitive ionizing fronts (streamers) occurring in the filamentary discharge, allows one to render an account of the transient evolution of the velocity field lines towards the stationary vortices. Although the numerical simulation could not be continued to a steady state, it shows that a small ring vortex is created near the point electrode, moves rapidly from the point to the plane and then begins to enlarge at the right (experimental) place.

An electrical corona discharge at atmospheric pressure in positive point-to-plane configuration creates an electric wind from the point to the plane which, within a few seconds, generates an axisymmetrical vortex in a closed cylindrical vessel (ring vortex). A first model for the establishment of this vortex was recently published and our study is an evolution based on an improved physical model. It does not include any empirical time scaling parameter, and takes into account the successive ionizing fronts as a varying electrical force due to the propagation of a sharp electrical field maximum acting on the space charge distribution along the interelectrode gap. After the front propagation (50 ns), the remaining positive ions drift (during 100 µs) in the slowly restoring electric field. Numerical simulations show that the very first streamers and remaining positive ions rapidly push the gas along the very narrow discharge volume, creating a small ring vortex at the cathode around the discharge axis. The following ones have a cumulative effect leading to the enlargement of the vortex. In a few seconds, a quasi-stationary distribution is obtained, which is very close to the experimentally observed steady state.