You are here
Model Development
ACOUSTCS HOME PEOPLE COVIS PROJECTS SOFTWARE & DATA PUBLICATIONS NEWS LINKS
This represents a potpourri of models which attempt to address the basic physical processes affecting particles in plumes. Most of these models are in the process of moving beyond just understanding and interpreting the acoustic imaging and Doppler data that Peter Rona, myself and many others have collected to trying to get at some of the physical processes and interactions controlling particles and particulate matter in plumes.
Modeling particle growth in plumes: Interpretation of acoustic and optical images of plumes depends on the particle size distribution. The size distribution of metallic sulfide particles reflects the delicate balancing of rapid upflow, rapid precipitation of sulfides, slow oxidation of sulfides to oxides, slow aggradation of smaller particles, and probably a host of other factors. I am in the processes of improving a published model (Bemis et al., 2006) of particle sedimentation in plumes to reflect directly this balancing of chemistry and dynamics. Fe sulfide precipitation rates are crucial as vent endmember Fe concentrations are needed to control the mass flux of particles into the plume and make quantitative predictions.
Particles and flow structures (with Prosenjit Bagchi): The spatial distribution of particles in a plume reflects the interactions of the particles with the swirling flow. Comparisons of direct numerical simulation of the Navier-Stokes equation and particle tracking with acoustic images are used to determine the relative behavior of particles and flow. The particles in the Grotto Vent plume appear to follow the flow in a fairly passive (but not conservative) fashion: see this summer’s Ridge 2000 newsletter for a summary of a paper in progress.
Local transport of particles, larvae and whatnot: Plumes entrain their surrounding in order to expand. This modifies the local velocity field. Hence current meter measurements in Main Endeavour Field reflect multiple interacting processes: tidal-driven currents and their reflections off topography, buoyancy driven rise of both diffuse and focused flow, and the entrainment into the rising plumes. I have developed a model of how multiple plumes modify the surrounding velocity field, which I want to compare with data on transport and with velocity measurements.
Optical modeling (with Kristina Bennett, Deborah Silver, and Min Chen): Particle composition varies extensively. The visible color of a plume is a function of particle composition – at the simplest, white smokers are “white” due to the dominant presence of anhydrite and black smokers are “black” due to metallic sulfides, many of which are grey. We have been modeling the optical appearance of plumes using the volume backscattering strength (from the acoustic imaging data of the Grotto Vent plume) as input. We then use cutting-edge 3D spectral rendering models to create images of the plume (see Santilli et al., 2004).