Seminars

The rail plasma actuator (RailPAc) is a device being developed at the University of Texas at Austin for aerodynamic flow control in atmospheric air. The actuator consists of parallel electrodes flush mounted to a ceramic plate. When a large pulse current (~1kA) at low voltage (~250V) is supplied, an electrical arc is generated and driven along the electrodes by a strong Lorentz force. The motion of the plasma arc induces flow in the surrounding air through both compression and entrainment. A study was conducted on a prototype RailPAc to characterize the Lorentz force and momentum transfer that are direct measures of the actuator control authority. The time resolved body force measurement used deconvolution and regularization techniques to infer the reaction force from the structural response of the RailPAc test stand. The momentum transfer to the surrounding air was assessed using a pendulum setup to relate the test stand displacement to the impulse delivered. High-speed imaging was used to characterize the  development and velocity of the arc. Actuation efficiency of the RailPAc was determined through analysis of current and voltage traces of the arc transit. Additionally, spectroscopic techniques were employed to study the temporal evolution of the arc temperature and composition. The results obtained prove the feasibility of the RailPAc concept and offer considerable insight into the dynamics of transient arcs.