Ronald L. Dougherty's Research
(Ph.D., Missouri University of Science & Technology)
Office: 3118 Learned Hall
Current and Recent Research
Radiative Transfer including Polarization Effects
From recent theoretical and experimental studies, it appears possible to “probe” fluid/particle suspensions with polarized light in order to characterize the particles in suspension. There are significant differences in the signals exiting the suspension, depending upon the type of polarized light used. In particular, the behavior of linearly polarized [laser] light as opposed to that of circularly polarized [laser] light is extremely interesting, and is the current area of interest in this research.
Dynamic Light Scattering
Laser light scattering from very "thin" fluid/particle suspensions can be used to determine the size of the particles suspended in the fluid and the viscosity of the fluid. Research is underway to extend this capability from "thin" suspensions to very dense suspensions - wherein the particles may occupy 2% - 10% of the total suspension volume. Both theoretical and experimental aspects of the problem are being addressed from two points-of-view: directly “handling” the multiple scattering in dense suspensions, and suppressing the multiple scattering to sift out the single scattering signals. In addition, both stagnant and flowing fluid/particle suspensions are being studied.
Two-Phase Heat Transfer in Oil and Gas Pipelines
This project involves the examination of open literature heat transfer coefficient correlations; the determination of important parameters affecting the heat transfer coefficient; and the improvement of those correlations. Project application is to the flow of multi-component multiphase fluid flow in pipes with orientations ranging from horizontal to vertical, considering laminar and turbulent flow regimes, and considering the various flow patterns that may arise in such flow situations.
Laser Doppler Velocimetry Applied to Filtration
This project is concerned with the use of an LDV system to determine the local characteristics of automotive filters. The LDV system allows for the non-intrusive study of particle laden air flow fields, and the very small size of the LDV probe volume makes it possible to obtain local data upstream and downstream of a filter, yielding local filtration efficiency results. These results have been compared to the theoretical predictions of other researchers in automotive air filtration.
Radiative Transfer including Reflection/Refraction Effects
When electromagnetic energy passes from one material to another (eg. air to water), the light waves are reflected and refracted. Depending upon the relative refractive index, the angle of incidence, material absorption and scattering characteristics, and material thickness, the change in the light wave intensity leaving the material can be significant. This work is directed toward computing those effects, comparing to measurements, and applying the results to a variety of semi-transparent material interfaces, such as those for air-water interfaces in solar ponds and larger bodies of water.
Radiative Transfer within Layered Materials
This research is studying, experimentally and analytically, the effects of layering fluids or layering particles suspended within those fluids upon a laser beam propagating through and reflected within the layers. The purpose is to explore various combinations of fluids and particles which could effectively trap the radiation within the material, increasing absorption. Application is directed toward better understanding of solar ponds and improvement of their efficiency.