Time-dependent volume force produced by a non-thermal plasma actuator from experimental velocity field

摘要

The electrohydrodynamic volume force produced by the Coulomb force acting on charged species in weakly ionized gas can improve the aerodynamic performances of academic and industrial turbulent flows. In this paper, a single dielectric barrier discharge is investigated with a focus on the experimental characterization of the time-resolved topology of the produced electrohydrodynamic volume force. The distribution of force over the volume of gas is calculated from velocity measurements by resolving simplified Navier-Stokes equations. Comparisons between the present calculated body force and data from the open literature confirm the accuracy of the method used. This study reveals that the unsteady force shows large fluctuations with an alternation of positive and negative longitudinal forces. The glow and streamer discharge regimes contribute differently to the electrohydrodynamic volume force. Both regimes promote a positive volume force longitudinal to the flow and a negative volume force in the transverse direction. However, the momentum transfer is significantly larger during the glow regime. A negative volume force (70% of the positive force amplitude) is observed following the glow phase, when there is no discharge. This negative volume force results from the local flow deceleration due to viscous influence at the wall and turbulent diffusion in the flow.