Engineering Commons^™

Influence Of Swirl And Turbulence In The Particle Removal Using Fog In A Pipe Flow, Nisarg T. Patel

All Theses

Fog-and-tube scrubbers are employed to remove harmful ultrafine aerosols, such as Diesel particulate matter (DPM), from an airflow. The underlying principle of this removal process involves enlarging the aerosol particles by coagulating them with fog drops, which are subsequently eliminated through inertial impaction onto the tube wall. Previous research conducted by Tabor et al. (2021) demonstrated an increase in scavenging of ultrafine DPM particles, ranging from 11.5 nm to 154 nm, by as large as 45% over the no fog case. This finding is crucial in addressing the challenges associated with conventional filtration methods for capturing ultrafine particles.

The present …

Optical Control System For Atmospheric Turbulence Mitigation, Martyn Lemon

All Theses

Propagation of laser light is distorted in the presence of atmospheric turbulence. This poses an issue for sensing, free-space optical communications, and transmission of power. With an ever-increasing demand for high-speed data communications, particularly between satellites, unmanned vehicles, and other systems that benefit from a point-to-point link, this issue is critical for the field. A variety of methods have been proposed to circumvent this issue. Some major categories include the manipulation of the light’s structure, an adaptive scheme at the optical receiver, scanning mirror systems, or a transmission of simultaneous signals with a goal to improve robustness.

There is an …

A Study Of The Statistics Of The Air/Water Interfacial Temperature Field During Mixed Convection Heat Transfer, Jie Kou

All Dissertations

Heat transfer across an air/water interface is of particular importance to limnology, oceanography and some industrial applications. The relationship between the statistics of the air/water interfacial temperature field and the interfacial heat flux is poorly understood, particularly for the mixed convection condition, which is a common heat transfer mechanism for small inland lakes. The few studies that have been conducted under mixed convection conditions have been limited to an uncontrolled surfactant condition (tap water). Therefore, in this dissertation research two sets of experiments for wind speeds from 0 to 4 m/s were conducted: controlled surfactant contaminated conditions (with oleyl alcohol) …

Experimental Study Of The Three-Stream Scalar Mixing In A Turbulent Coaxial Jet, Matthew Dinger

All Theses

In the present study we investigate three-stream scalar mixing in a turbulent coaxial jet. In
this flow the center jet and the annulus, consisting of acetone-doped air and ethylene respectively, are
mixed with the co-flow air. A unique aspect of this study compared to previous studies of three-scalar
mixing is that two of the scalars (the center jet and air) are separated from the third (annulus);
therefore, this flow better approximates the mixing process in a nonpremixed turbulent reactive
flow. Planar laser-indiced fluorescence and Rayleigh scattering are employed to measure the mass
fractions of the acetone-doped air and ethylene, respectively. …

Numerical And Physical Modeling Of Turbulent Shear Flows, John Raiford

All Dissertations

This dissertation is an evaluation of popular turbulence schemes; both three dimensional and depth-averaged, and also includes an experimental study on shallow near bed jets. The three dimensional and RNG turbulent closure schemes are evaluated for free and bounded shear flows. For free shear flows (circular and plane turbulent jets), the scheme with standard coefficient performs equally well and in some cases better than the renormalized group scheme in predicting growth rate, decay of centerline velocity and longitudinal velocity profiles. For turbulent kinetic energy across the jet, the inner region is better predicted by the RNG scheme.
The second case …

Investigation Of The Effects Of Subgrid-Scale Turbulence On Resolvable-Scale Statistics, Qinglin Chen

All Dissertations

The effects of the subgrid-scale (SGS) turbulence on the resolvable-scale statistics and the effects of SGS models on large-eddy simulation (LES) are studied. It is shown that the SGS turbulence evolves the resolvable-scale joint probability density function (JPDF) through the conditional means of the SGS stress, the SGS scalar flux, and their production rate, which must be reproduced by the SGS model for LES to predict correctly the one-point resolvable-scale statistics, a primary goal of LES. This necessary condition is used as the basis for studying SGS physics and for testing SGS models. Theoretical predictions, measurements data obtained in a …