Characteristics of a spark discharge as an adjustable acoustic source for scale model measurements

Christophe Ayrault (1) , Philippe Béquin (1) , Sophie Baudin (2)

1 LAUM - Laboratoire d'Acoustique de l'Université du Mans
2 LaMCoS - Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne]

The simulation of acoustic phenomena using urban street scale models requires the use of a small and powerfull sound sources with a wide frequency bandwidth and omnidirectional radiation. Among different source types able to provide these characteristics, spark discharge in air is an interesting solution. The principle is based on the generation of an electric discharge by applying a high voltage between two electrodes. First the gas becomes electrically conducting, the electric current heats up the gas, causing the formation of an impulsive sound signal. These sources have been also widely used for shock wave propagation, like sonic boom, for which propagation is non linear. However, the behaviour of spark discharges and their acoustic radiation depend greatly on the electrodes gap. As very little investigation has been done of this dependance, this work provides a detailled characterisation of a spark discharge in function of the electrodes gap. Electrical characteristics, repeatability, acoustic characteristics and the limits between linear and non linear propagation domains are studied in function of various electrodes gaps. This experimental study is meant to be a useful resource for experimenters to design a spark discharge adapted to their specific applications.

Domaines: Acoustique [physics.class-ph]

Christophe Ayrault, Philippe Béquin, Sophie Baudin. Characteristics of a spark discharge as an adjustable acoustic source for scale model measurements. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00810828⟩