Étude des transferts de masse et de chaleur dans la grotte de Lascaux : le suivi climatique et le simulateur - Persée

Etude des transferts

de masse et de chaleur

dans la grotte de

Lascaux : le suivi climatique

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Introduction

La grotte de Lascaux, découverte en 1940 à Montignac en Dordogne, dans la vallée de la Vézère, figure au patri¬ moine mondial de l'Unesco.

montré un impact négligeable de ce retrait sur l'équilibre de la cavité.

Au cours du temps, les tempéra¬ tures et les conditions hydriques du milieu environnant ont souvent changé [Malaurent et al. 2006 a]. Sous l'influence d'échanges et de transferts

apparition of the micro-organisms in order to stop their propagation. Among the measures taken by the committee, a better understanding of the flows in the cave was considered very important, and has induced the creation of a simulation tool, the "Lascaux Simulator". The non-intrusive character of simulation is one of the major assets of this method. The numerical simulation in fluid mechanics is here dedicated to the conservation of the cave of Lascaux. The simulator is based on a computational fluid dynamics code named Aquilon. A three dimensional survey has been done in the cave using laser scanning. An accurate topology of the environment is incorporated in the simulator. Starting from this point, governing equations of the fluid mechanics are solved and parameters such as temperature, velocity or moisture content are known in every point of the cavity. Thermal conditions are chosen based on the analysis of the calculated and measured temperature data for more than 50 years. In this article, two configurations are presented, the first one in September 1981, a period during which the cave remained in a stable state regarding condensation, and the other one in December 1999; at this time, temperature was reversed, the ground of the cavity was colder than the ceiling.

This phenomenon implied an inversion of the air flow in the cave. Finally, the removal of the dividing wall of the "Bauer airlock" has been simulated, and it has been shown that the impact on the cavity would be negligible.

d'énergie avec le milieu extérieur, le système formé par la grotte de Lascaux a évolué et ses variables d'état ont été modifiées. Les changements climatiques ont des conséquences dont on peut

D. LACANETTE, Ph. MALAURENT, J.-P. CALTAGIRONE et J. BRUNET, Etude des transferts de masse et de chaleur dans la grotte de Lascaux

KARSTOLOGIA n°50, 2007 » 19-30

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