HR: 0800h
AN: AE31A-0024    [Abstracts]
TI: Three Dimensional Behaviour Analysis Of Lightning Channel By CFD Modelling
AU: * Chemartin, L
EM: laurent.chemartin@onera.fr
AF: ONERA/DMPH/FPA, 29 av de la Division Leclerc, Chatillon, 92322, France
AU: Lalande, P
EM: philippe.lalande@onera.fr
AF: ONERA/DMPH/FPA, 29 av de la Division Leclerc, Chatillon, 92322, France
AU: Laroche, P
EM: pierre.laroche@onera.fr
AF: ONERA/DMPH/FPA, 29 av de la Division Leclerc, Chatillon, 92322, France
AU: Delalondre, C
EM: clarisse.delalondre@edf.fr
AF: EDF/R&D/MFEE, 6 quai Watier, Chatou, 78400, France
AU: Cheron, B
EM: bruno.cheron@coria.fr
AF: CORIA, Site Universitaire du Madrillet, St Etienne du Rouvra, 76801, France
AU: Andreu, H
EM: herve.andreu@dga.defense.gouv.fr
AF: CEAT, 47 route de Saint Jean, Balma, 31130, France
AB: One of the mechanisms assumed to be involved in the ignition of the recoil streamers phase is associated with the development of instability in the lightning channel. Like any other electric arcs, lightning channels become unstable if the provided power is insufficient. A criterion has been derived from Heckman (1) who shows the minimum current to sustain an electrical channel in air as a function of its length. In order to study this phenomenon, ONERA in collaboration with EDF has performed 3D simulations of a part of the lightning channel in order to compute the main characteristic of the arc and understand in the future the physical conditions for the ignition of instability. In a first step, purpose of this paper, the computations have been compared to the experiment of Tanaka et al (2). They have experimentally studied free burning arcs of 1.6 and 3.2 meter long, subjected to continuous current of 100 and 2000A with duration higher than 100ms. The results show that the characteristics of the arc column do not depend on the gap length, which means that the electrodes have no effect on it. Consequently, the electrical arc produced is very similar to a part of the lightning channel. (1) Heckman S., Why does a lightning flash have multiple strokes? Thesis (PH.D.), Massachusetts Institute of Technology, 1992 (2) Tanaka S., Sunabe K. and Goda Y., Three Dimensional behaviour analysis of D.C. free arc column by image processing technique, XIII Intl Conf on Gas Discharges and their applications, Glasgow, 2000
DE: 0654 Plasmas
DE: 3324 Lightning
DE: 3367 Theoretical modeling
SC: Atmospheric and Space Electricity [AE]
MN: 2007 Fall Meeting