The Principal Investigator (PI) plans to fabricate and test a prototype instrument in an effort to obtain specialized measurements describing the behavior of small-scale convective (i.e. thermally-driven) vortices in the atmosphere. Convective vortices range in size from small short-lived gyres (such as "dust devils") to far larger and more persistent hurricane-class circulations, and play an important role in vertical transports of heat, momentum and tracer species such as dust and other forms of aerosol. The PI recently advanced a generalized theory for these vortices that includes the effect of irreversible thermodynamic processes (tracing to air's viscosity and resulting turbulent losses of momentum) and other sources/sinks of energy. This theory provides a mathematical expression relating pressure and flow speed that sheds new light on their observed intensity and basic structural features, including their tendency to exhibit hollow (or "calm eye") type structure. The PI will direct a full-time graduate student and laboratory technician in the design, fabrication and testing a Prandtl-tube data acquisition system capable of obtaining pressure measurements needed to properly test this theory. This instrument, which will be mounted on a short tower suitable for remote deployment, will simultaneously measure both static and dynamic (stagnation-generated) fluid pressures at required resolution, and will incorporate detection of charged particles that can in turn be linked to the presence of banded flow structures known to occur within some dust-filled circulations.
The intellectual merit of this effort derives from improved basic understanding of the dynamics governing rotational atmospheric flows on a wide variety of scales. Broader impacts of this exploratory effort will come primarily through support for education of a graduate student, but could ultimately extend to improved representations of processes responsible for lifting of dust from vast expanses of desert (and associated climate system impacts) to detailed predictions of damaging storms such as thunderstorm-spawned tornadoes.
