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A computer model simulating moisture migration in soil from a drip source considering root water extraction (RWE) was developed. The model was formulated using Continuous System Modeling Program (CSMP). / A two-dimensional non-linear unsaturated transient flow equation was solved using the principle of mass conservation and Darcy's law on soils of dwarf-apple orchards located in southwestern Quebec. A finite axisymmetric cylinder with homogeneous, isotropic and non-swelling soil was considered for the simulations. No flow conditions across the boundaries of the cylinder were fixed. The initial soil moisture contents in the soil profile observed in the field were input for the simulations. / The macroscopic approach was used to compute RWE as a function of (THETA), Z and t. The RWE was assumed to be equal to evapotranspiration (EP) which was estimated using temperatures and the solar radiation index of the location. / The moisture contents in the soil profile observed at the termination of emitter discharge were in close agreement with the simulated values. The soil moisture distribution was found to depend on the amount of water remaining in the soil and soil moisture retention characteristics. It is independent of the rate of emitter discharge, the depth of root zone and method of application.

A wooden, perforated, uniform cross-section duct was examined to determine the optimum levels of aperture ratio and fan speed with respect to uniformity of discharge. The optimum aperture ratio for the 8.54 m long duct was 1.0 with a uniformity coefficient of 90.28%. The fan speed had little effect on the uniformity of discharge. The friction factor was experimentally determined to be 0.048 for a non-perforated duct and this value was assumed to be the same for a perforated duct of similar construction. A kinetic energy correction factor was used to analyze the flow in the duct. Values for this correction factor were determined from experimental data. Values of the coefficient of discharge and the total duct energy were calculated. A mathematical model was proposed based on the conservation of momentum and the Bernoulli's equation. The model responded favourably and predicted the duct velocity nearly perfectly and slightly underestimated the total duct energy.

Using a two-dimensional nonlinear numerical simulation of a (viscous) stratified shear layer, strong instabilities resulted from the resonant interaction of a long linearly neutrally stable wave and the corresponding fastest growing wave. This linearly fastest growing wave, with optimal initial conditions, grows initially at a rate five times that predicted by linear theory. With other initial conditions, the linearly fastest growing wave may actually decay. The possibility of this type of interaction is suggested by the weakly nonlinear theory (cf. Maslowe, 1977). This coupled system of fourth order nonl inear partial differential equations was solved using a modified pseudospectral scheme for the spatial variables, incorporating the use of fast Fourier transforms to calculate spatial derivatives, and a second order Adams-Bashforth scheme for the temporal derivatives . / Dans cette etude, en utilisant une simulation numerique nonlineaire a deux dimensions d'une couche stratifiee, decollee et visqueuse, on obtint des resultats interessants a partir des cas correspondant a l'interaction resonnante d'une onde longue a stabilite neutre et d'une onde courte qui croit la plus rapidement selon la theorie lineaire. En utilisant certaines conditions initiales, l'onde courte croit initialement a un taux cinq fois superieur a celui predit par la theorie lineaire. Avec d'autres conditions initiales l'onde courte decroit. La possibilite de ce genre d'interaction est predite par la theorie faiblement nonlineaire (voir Maslowe, 1977). Ce systeme couple aux equations nonlineaires du quatrieme ordre aux derivees partielles, est resolu par une methode pseudo-spectrale modifiee, pour les variables spatiales, et une methode Adams-Bashforth du second ordre pour les derivees temporelles. fr

Air distribution ducts are used in the environmental control of livestock and poultry building as well as the conditioning of most agricultural produce. / In order to simplify the approach to the design of ventilation ducts, a mathematical equation has been derived to describe the average air velocity of a duct. / The primary objective of the research work was to test goodness of fit of an equation describing the average air velocity of perforated ventilation ducts, under balanced as well as unbalanced air distribution: $V = H sb{o}{X over L} + (V sb{L}-H sb{o}) {X sp2 over L sp2}$. / This equation was successfully tested using data measured from 14 ducts of constant cross-sectional area, built of wood or polyethylene with outlets of various shapes and aperture ratios. Results indicated that aperture ratio and distance along the duct are the two most significant factors influencing the average duct air velocity values, but material and outlet shape had little effect.

Bibliography: leaves 117-126 / vii, 126 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied Mathematics, 1993

by Michael B. McIllrath. / Bibliography: leaves 47-52. / Prepared under grant DOT/TSC 849. Originally presented as the author's thesis, (B.S.) in the M.I.T. Dept. of Electrical Engineering and Computer Science, 1976.

Orientador: Katia Lucchesi Cavalca / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-17T18:45:51Z (GMT). No. of bitstreams: 1 Brol_KeilaBelquiz_M.pdf: 7087689 bytes, checksum: b81e96d33b1146da143fae0859da2363 (MD5) Previous issue date: 2011 / Resumo: O desenvolvimento de modelos matemáticos que visam simular as características operacionais das máquinas rotativas é importante para representar uma variedade de fenômenos expressivos que se manifestam durante a operação, para tanto é necessário a modelagem dos componentes que caracterizam o comportamento dinâmico do sistema. Este trabalho tem por objetivo determinar os parâmetros físicos que integram os selos de fluxo de folga fixa e angular ao modelo global de sistemas rotativos. As rigidezes e os amortecimentos são obtidos através da solução de equações governantes para líquidos escoando em selos anulares pelo método clássico das perturbações de ordem máxima um e a solução da ordem zero permite demonstrar a variação da pressão e velocidade para as equações de ordem zero. Os resultados obtidos foram validados com os valores apresentados pela literatura. O resultado deste trabalho poderá ser aplicado na modelagem global de uma máquina rotativa, de modo a tornar a análise mais completa do conjunto girante / Abstract: The development of mathematical models designed to simulate operational characteristics is important to represent a wide variety of expressive phenomena that manifest during the operation, and therefore it is necessary the components modeling that characterize the system dynamic behavior. This study aims to determine the physical parameters that influence the flow seals to fixed angles and variables in the global rotating systems model. The stiffness and damping are obtained by solving the governing equations for fluid flowing in the annular seals using the classic perturbation method of maximal order one. The zero-order solution allows to demonstrate the pressure and speed variation to zero order. The results were validated with the similar tests reported in the literature. This work results are eligible to be applied to model a global rotating machine in order to make a more complete rotor analysis / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

A finite element numerical model is developed for the modeling of coupled surface-water flow and ground-water flow. The mathematical treatment of subsurface flows follows the confined aquifer theory or the classical Dupuit approximation for unconfined aquifers whereas surface-water flows are treated with the kinematic wave approximation for open channel flow. A detailed discussion of the standard approaches to represent the coupling term is provided. In this work, a mathematical expression similar to Ohm's law is used to simulate the interacting term between the two major hydrological components. Contrary to the standard approach, the coupling term is incorporated through a boundary flux integral that arises naturally in the weak form of the governing equations rather than through a source term. It is found that in some cases, a branch cut needs to be introduced along the internal boundary representing the stream in order to define a simply connected domain, which is an essential requirement in the derivation of the weak form of the ground-water flow equation. The fast time scale characteristic of surface-water flows and the slow time scale characteristic of ground-water flows are clearly established, leading to the definition of three dimensionless parameters, namely, a Peclet number that inherits the disparity between both time scales, a flow number that relates the pumping rate and the streamflow, and a Biot number that relates the conductance at the river-aquifer interface to the aquifer conductance. The model, implemented in the Bill Williams River Basin, reproduces the observed streamflow patterns and the ground-water flow patterns. Fairly good results are obtained using multiple time steps in the simulation process.

Experimental studies on infiltration/soil-water movement processes are vital to better understanding movement of soil-water in the vadose zone. The objective of this experimental research was to investigate infiltration/soil-water movement processes utilizing laboratory experiments and computer modeling. Small scale laboratory soil box infiltration experiments were conducted and utilized for the improved parameterization of the Green-Ampt (GA) saturated moisture content parameter to produce an effective moisture content parameter (Be) for utilization in a modified GA model. By incorporating ⊖e values into GA modeling, modeling results showed greatly improved wetting front prediction across different soil conditions. A new soil packing method was proposed for replicating complex microtopographical surfaces with uniform bulk densities in laboratory soil box experiments which proved efficient and effective at accomplishing both objectives. A rainfall simulator and an instantaneous-profile laser scanner were used to simulate rainfall and quantify surface microtopography for experiments. The results clearly show the effect of microtopography on infiltration and soil-water movement characteristics. This offers valuable insight into infiltration/soil-water movement processes as affected by different soil and surface microtopographic conditions. / National Science Foundation (Grant No. EAR-0907588)