On a bi-layer shallow-water problem

Abstract In this paper, we prove an existence and uniqueness result for a bi-layer shallow water model in depth-mean velocity formulation. Some smoothness results for the solution are also obtained. In a previous work we proved the same results for a one-layer problem. Now the di culty arises from the terms coupling the two layers. In order to obtain the energy estimate, we use a special basis which allows us to bound these terms.

Upslope fire and eruptive fire

International audienc

Fire Intensity

International audienc

Generalized Blaze Flash, a "flashover" behavior for forest fires - Analysis from the firefighter's point of view

International audienceThe phenomenon called ‘flashover’ or ‘eruptive fire’ in forest fires is characterized by a sudden change in fire behavior: everything seems to burst into flames instantly and firefighters are over-whelmed by a sort of eruption, spreading at a speed at far several meters per second. Unfortu-nately it has cost several lives in the past. The reasons for such an accident always create contro-versy in the Research field. Different theories are highlighted and especially two major axes are currently subject to discussion because they are very popular among people involved in fire-fighting. The one with regard to VOCs emissions is the best-known among firemen. Under great heat, during summer or with a fire approaching, plants emit VOCs and the more the temper-ature grows, the more the amount of VOCs emitted grows. Under specific conditions (essentially topographical, meteorological and atmospheric) the cloud of gas can accumulate in an appropriate zone. The concentration of VOCs may therefore reach the Lower Explosive Limit, triggering the burst of the cloud when in contact with the fire. The second theory depends on physical considera-tions. An example is based on a convective flow created by the fire itself. When a fire spreads on a slope, it creates an aspiration phenomenon in a way to supply the fire with oxygen. The more this phenomenon is important, the more the flames tilt and increase the rate of speed, needing even more oxygen and thus induced flow. This vicious circle can stabilize or have an erratic behavior to trigger off a fire eruption. This article presents these two theories, and especially the new advanc-es on this research subject

A review of current knowledge of wildfire firefighter safety zones

International audienc

How 10 years of physical assumptions led to the development of the Balbi model, from labor-atory scale to field scale

International audienc

Fuelbreaks: a part of prevention

International audienc