Experimental and numerical investigation of a flow induced by a pulsed plasma column

Abstract

The paper studies, both experimentally and numerically, a high-speed transient flow induced by a pulsed volume discharge in still air at low pressure. It is shown that, in the constricted mode, the discharge is capable of producing uniform deposition of the electrical energy into a long (24 mm in length), thin (less than 2 mm in radius) plasma column. Flow visualization experiments using particle image velocimetry (PIV) and high-speed shadow imaging indicate that this pulsed localized energy deposition generates a highly symmetrical cylindrical shock wave expanding at an average speed of 550 m/s within the first 40 μs after the discharge. Three-dimensional computational fluid dynamics (CFD) simulations successfully reproduce the experimentally observed flow structures and provide better insight into the complex discharge-induced flow. Modeling the trajectories of “virtual” particles within the CFD-predicted flow yields excellent agreement between numerical and PIV flow velocity profiles, and this comparison is used to quantify the rates of “rapid” energy thermalization in the pulsed discharge.