Spatial variation of soil moisture content under a sub-surface drip irrigated field was studied. Conventional statistics and geostatistical methods were used to analyze the relation between four soil variables: % sand, % silt, % clay, and soil moisture content. The soil moisture content was measured before, during, and after irrigation using tensiometers. The samples were collected from 63 sites on a 180 by 244 meters (4.45-hectare) cotton field. The pre- and post-irrigation soil moisture content shared the same spatial structure, differing only by the magnitude of their variances. After any irrigation the soil wetter points remained wetter and the drier points remained drier. It was found that the spatial patterns of soil moisture content appear to be stable over time. The ranges obtained from the variograms before and after an irrigation had the same magnitude of influence. The coefficient of uniformity obtained using the gravimetric method was 92.4 %, however, using tensiometers values ranged from 84.4 to 87.3%.

In the incineration of liquid hazardous wastes there exist "rogue" droplets (>300 μm diameter) which penetrate past the flame zone and burn as isolated droplets in the postflame gasses. Detailed knowledge of the droplet burnout points are essential to keeping the destruction removal efficiency in excess of the 99.99% required. The spread in trajectory endpoints of individual evaporating droplet streams injected into a turbulent combustor was investigated numerically. Results are in good agreement with the measurements. Correlation between the spread in the burnout points and initial droplet size, initial droplet velocity, interdroplet spacing, and droplet injection angle were investigated. The numerical investigation utilizes the novel One Dimensional Turbulence (ODT) {Kerstein (1999)} for the time developing fluid velocity and temperature fields with a new two phase flow model for predicting particle trajectories. The droplet heating/burning model used by Mulholland et al. (1991) is modified for application to this thesis.

This thesis describes the creation of a dynamics model of an autonomous underwater vehicle. Motion equations are integrated to obtain the position and velocity of the vehicle. External forces acting on the vehicle, such as hull and control plane hydrodynamic forces, are predicted for the full 360° angle of attack range. This enables the simulation of high angle of attack situations. An accurate through-body thruster model is also incorporated into the simulation. The vehicle model is validated using experimental turning diameters of the ARCS vehicle.

No description available.

The present study formulates the mathematical model for analyzing the penetration length and transport phenomena of a viscous reacting fluid injected into a two-dimensional heated slot. The application of the results are in clarifying the use of a reacting fluid to seal fracture in geothermal formations to prevent circulation loss during drilling geothermal wells. A methodology and a computer code have been developed which incorporate SIMPLE and MAC schemes, and which is capable of simulating a moving free surface boundary at the leading front with constant volumetric flow rate and with variable properties and exothermic chemical heat generation is suggested and developed. The constitutive and kinetic equations for the applied fluid are similar to an RIM type of material. Special attention is put on the kinematics of fountain flow and effects of hydrodynamic boundary conditions on the overall hydrodynamic phenomena. The effect of the gellation crust is briefly discussed.

An air jet emanating from a rectangular conduit with exit plane dimensions 7.62 cm x 1.27 cm (aspect ratio 6:1) is forced using four piezoelectric actuators mounted along the long sides of the jet opening. Excitation is effected via amplitude modulation of the resonant carrier waveform. Although the flow is not normally receptive to excitation at the actuator resonance frequency, if the excitation amplitude is high enough, spreading of the forced segments of the jet shear layer can lead to a significant deflection of the jet column. When the amplitude modulated excitation is high enough, the input waveform is effectively demodulated by a nonlinear process related to the formation and coalescence of nominally spanwise vortices. The resulting effect is the spatial amplification and attenuation of the modulation and resonant wavetrains, respectively. The choice of different spatial/temporal wavetrains can result in the excitation of spanwise and streamwise instabilities of the jet column.

Unsteady flow through an earthen dam has been investigated using the Boundary Element Method in which the upstream reservoir level may vary in a cyclic manner. The seepage surface at the upstream face is included in the computer model when the water level drops in the upstream reservoir. The use of this model has been illustrated by studying the variation of the phreatic surface in a beach along the Colorado river in the Grand Canyon. The potentials at various internal points are also calculated and compared with those measured in the field. Very good agreement is obtained between the results using the Boundary Element Method and field data.

Effective cooling of electronic components arranged in vertically oriented parallel boards is considered. The objective of the present investigation is to examine the effects of global flow in a channel upon the local heat transfer from a flush mounted source. The concept of adiabatic heat transfer coefficient and its application is clarified by reviewing its origins and examining a series of numerical experiments on a well-defined model problem. Simulations are conducted in the regions of laminar forced flow, mixed forced and local buoyant convection and buoyancy-induced flow. Local buoyancy effects cause a departure of adiabatic heat transfer coefficient from its value for pure forced convection. Calculations cover the range 10-3 at Pr = 0.7. The superposition principle for temperature fields is validated for forced convection. The effects of mixed convection upon this phenomenon is subsequently examined.

With increasing necessity to integrate CAD and CAM, it is necessary to develop more accurate models for predicting the performance of manufacturing processes. Conventionally, process parameters are selected by the process planner based on his experience. For CAD-CAM integration to be meaningful, it should be possible to arrive at the same decisions using computer models for that process. The end milling process is selected for such modeling. The parameters considered are process variables, cutter geometry, cutter material properties, workpiece material properties, workpiece geometry and location and properties of inclusions (if any) in the material. Dynamic Model for end milling is developed and successive iterations are performed to arrive at the speed and feed required to generate a given surface finish and tolerance.

<p> Nationwide process heating in the manufacturing sector accounts for 7,815 trillion BTU of energy use annually; this is roughly one-third of the sector's total energy consumption [Energetics Incorporated, 2014]. The U.S. Department of Energy estimates that seventy percent of process heating is fueled by the onsite burning of fossil fuels [Energetics Incorporated, 2014]. These fuel-fired process heating applications are prime opportunities for heat recovery projects capable of saving energy and, consequently, reducing operating costs. This thesis evaluates different methods for heat recovery in the Milwaukee manufacturing facility of STRATTEC Security Corporation. As a basis for this work, the overall energy usage of the facility is evaluated and the largest process heating and cooling loads are identified. Systems that will be evaluated include the zinc melt furnace, the low pressure steam system and the chilled water system. The energy recovered can be used to improve the efficiency of the source piece of equipment, to meet other process heating needs in the facility, or to generate electricity. These systems also can benefit from receiving energy recovered from a power generating process. Models of the energy and exergy balances in these systems are developed to predict the potential reduction in operating costs when heat recovery is implemented in the STRATTEC facility. In addition, the models and energy use information are used to identify inefficiencies in the systems that should be addressed before heat recovery is applied. Finally, a thermo-economic analysis is used to compare the various heat recovery options and select the most cost effective plan for implementing heat recovery. This analysis found that, for the existing equipment, heat recovery could not be implemented economically. However, opportunities for cost savings exist in the selection of new equipment to replace aging systems. Specifically, it was found that heat recovery could be implemented economically by replacing the existing chiller with an absorption chiller system that used waste heat from a power generation system.</p>