Research objectives and content
Main aim is to understand the physical principles that govern the dispersal of tephra during eruptions and to produce the first general models of disper- -sal in wind-blown volcanic plumes. The approach will be to develop fluid-dy- -namically based parameterisations of the time averaged velocity field in the plumes as it gains horizontal momentum from the wind.The models will be tested against laboratory data on sedimentation from plumes in a cross- current and from field studies, including tephra deposits from volcanoes in Ecuador and from the 19951996 explosive eruptions of Ruapehu Yolcano (New Zealand). Some complexities will be investigated including: effects of Reynolds number of particle setting and tephra layer thinning; aggregation of fine particles; various kinds of atmospheric motions from small-scale turbulence to large-scale rotational flows; possibility of convective insta- bilities at the base of wind-advected plumes. The models will be developed into a software package that can be used in volcano observatories and by civil authorities to mitigate the effects of volcanic ash.
Training content (objective, benefit and expected impact)
Training will be provided in the fluid dynamics, volcanology, computer model ling and experimental research, using the laboratory facilities at Bristol.
Links with industry / industrial relevance (22)
The principles that govern dispersal of particles by naturalplumes must also apply to industrial plumes.