Arvikar, Rameshwar Jagannath,
Thesis--University of Wisconsin. / Phtotcopy of typescript. Ann Arbor, MI. : University Microfilms International, 1976. -- 21 cm. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 322-348).
Thesis (M.S.)--University of Wisconsin--Madison, 1968. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
Hillestad, R. J.
Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.
Monserud, Robert A.
Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 138-156.
Partain, Seth Collins.
(has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Douglas S. Cairns. Includes bibliographical references (leaves 76-79).
19 January 2018
This dissertation presents a numerical analysis of the separated flow and convective heat transfer around a bluff rectangular plate. This geometrically simple “prototype” configuration exhibits all the important features of complex separated and reattaching flow and has the advantage of well defined upstream conditions. The main objective of this work is the investigation of three-dimensional, high Reynolds number, unsteady separated flow using the large eddy simulation technique. However, two-dimensional and three-dimensional low and moderate Reynolds number simulations leading up to this are also of interest. A staggered grid, finite volume method is used in conjunction with a third order Runge-Kutta temporal algorithm. The linear system for pressure is solved by, depending on the case, either a direct method or an efficient conjugate gradient with preconditioning. Two spatial discretizations are used, QUICK and CDS. In order to avoid the numerical diffusion effect from QUICK and dispersive effect from CDS, a mixed discretization is also introduced at high Reynolds number (Red = 50,000). The two-dimensional steady and unsteady simulations are first presented. The predicted flow characteristics are in agreement with those reported in previous numerical studies. The two-dimensional unsteady simulations ( Red = 1,000) provide good insight into the overall dynamic features of separation process, onset of instabilities and pseudo-periodic pattern of vortex formation, pairing and shedding. The realism of the simulation is however constrained by the artificially high coherence of the flow imposed by two-dimensionality. The three-dimensional simulations provide a much improved representation of the flow. Three-dimensional instabilities are found to appear soon after the onset of the shear layer roll-up, and result in the rapid break-up of spanwise vortices. Convective heat transfer simulations highlighting the important role of large scale structures in enhancing turbulent transport are also presented. At high Reynolds number, Red = 50,000, simulations are performed with three subgrid scale models. The selective structure function model, which allows improved localization, yields excellent agreement of the mean flow statistics with available experimental data. The dynamics of the flow is investigated using wavelet transform analysis and coherent structure identification. Characteristic frequencies related to shear layer instability, flapping and vortex shedding are identified consistent with experimental observation. The flow in the reattachment region is highly intermittent and characterized by a complex quasi-cyclic growth and bursting of the separation bubble, and horseshoe structures are identified in the recovery region of the flow. / Graduate
31 March 2010
The purpose of the study was to determine whether business simulations helped further systems thinking in individuals. To establish whether improved systems thinking may be a result of participating in business simulation programs, participants needed to be separated from their day-to-day reality and confronted with managing their organisations in a virtual world. The virtual world in which participants needed to immerse themselves was a customised business simulation designed to capture some of the critical elements of their organisation in a simplified virtual micro-world. This new world allowed participants to engage with and experiment with their organisations in a risk free environment and from a holistic systems perspective. Experimental research was conducted to determine whether it may be possible that individuals participating in these business simulation programs experience a shift in mental models towards systems thinking. The feedback received from participants showed high levels of agreement with respect to the fact that the simulation tools allowed them to engage with the virtual model from a systems perspective. Approximately a third of all participants reported that their most significant insight during the simulation program was in some way related to their new way of seeing and understanding the system of which they are part. The study concludes with the notion that organisations should further encourage systems thinking, which will help them deal with the complexity of the environment in which we operate on a day-to-day basis. Furthermore, improved systems thinking may help us overcome some significant barriers to learning and thereby improve our capabilities in respect to dealing with change. Further research is needed to better qualify the specific skill sets necessary for improved systems thinking. / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted
Intensive study of the growth of individual trees in the open and in stands, and of the growth of stands themselves, has provided the basic biological assumptions and equations, which then are used in simulation of stand growth. Simulation, emerging as a research technique since the advent of electronic computers, has helped solve many forestry problems previously considered unmanageable. Simulation is almost essential in building stand growth models. Stand growth models for lodgepole pine (Pinus contorta Doug.)¹, are needed to illustrate some economic consequences of alternative methods of management. Such analyses can provide guidelines for improved stand management. These better approaches are desirable because lodgepole pine is required to supply increasing demands of a rapidly developing pulp industry in British Columbia and in Alberta. Newnham's stand models are critically examined and fully described. A revised simulation model is built and the methods used are described. Principles and assumptions basic to the development of stand models in general are also outlined. The revised model is initiated with a 30 x 30 tree matrix. The dbh frequency distribution of these 900 trees is normal. A mean dbh of 1.2 inches at 15 years, with a standard deviation of 0.4 inches, is assumed to represent site index 70 feet at 80 years. The dbh growth of each of the 900 trees is predicted by 5-year periods using a regression of dbh on age for open-grown lodgepole pine, with appropriate reductions for crown competition. The crown width of each of the 900 trees is calculated from the regression of crown width on dbh for open-grown lodgepole pine trees. A factor is introduced to reduce the calculated crown width, as trees grow from open-grown initially to forest-grown conditions. Tree height is calculated from the multiple regression equation of height on dbh and basal area per acre. Individual tree volumes are calculated from ratios of volume to basal area for various heights. Techniques of testing confidence in the prediction of stand parameters are illustrated for the revised model. Combined standard errors of estimate (in per cent) are used to indicate the error estimates for the simulation model. These are large but, by comparison with all available data on tree growth and stand yield, the revised simulation model satisfactorily describes the growth of lodgepole pine stands in all four spacings tested. Moreover, much of the information calculated for each 5-year period cannot be obtained from conventional yield tables. In order to analyze the economic consequences of harvesting various kinds of products, yields of 8-foot logs and ratios of section volume to tree volume are calculated for ages 20 to 100. Maximum gross yields will come from 3.3 ft. x 3.3 ft. initial spacings. However many small trees included in gross yield estimates will be less than 6 inches in dbh and therefore not merchantable. The full range of influence of tree size on costs and values per tree is illustrated. Ratios of lineal feet per acre to cubic volume per acre are used to adjust logging and milling costs for tree size, based on the average cost per cunit which applies to lodgepole pine trees averaging about 11 inches in dbh. In all cases tested, initial spacings of 13.2 ft. x 13.2 ft. give the best net return per acre from plywood and lumber. Production of lumber is next best. Poles and piling are less attractive, under the present assumptions. Production of pulp chips alone would create a loss at present market value. Results are summarized in two comprehensive wood and product value yield tables (Tables 5A and 55). These tables may improve decision-making concerning initial spacing. The revised simulation model also can be used to simulate, in a few minutes, the growth of many other kinds of lodgepole pine stands from age 15 to age 100, or more. Economic consequences of many approaches to managing lodgepole pine can be illustrated now. Although greatly improved economic and biological data are desirable, the revised model can provide good preliminary answers to many important questions about management of lodgepole pine. / Forestry, Faculty of / Graduate
Birchmore, Michael John
Forest planning is characterised by the necessity to satisfy a series of long term objectives and yet still to meet a series of short term objectives. This problem of conflicts is particularly pertinent to the Province of British Columbia where the forest ownership and the forest operator are each, primarily concerned with different time spectra. Further, the demands that are being made on the forest resource are becoming ever more stringent and demanding as the political and environmental awareness of the public increases. The need to consider multiple objectives in the planning process causes the inadequacies of many of the earlier models to be highlighted. A new series of models for forest planning is called for. The development of operations research, techniques and improved computers has facilitated the introduction of a new series of planning models. Many models have been developed using the optimising techniques of linear and dynamic programming for example, but the technique that, through its flexibility and latitude for variation in the basic assumptions, holds the most promise is simulation. Under the conditions of British Columbia, the forest firm, which is the main influence on the forest resource and links the natural environment with the socio-economic environment, is the natural planning unit. The firm is constrained by the superior environments and it is the responses of the firm to changes in either that affects the flow of goods and services from the forest. An analysis of the firm shows that if a systems approach is adopted the planning and productive stages of the firm may be defined in a suitable manner for the construction of a computer simulation model. The model may have several stages of operational development and may be used for different purposes as it is developed towards full operational use. The ultimate stage of development will only be known when the detailed construction of the model is undertaken. This thesis outlines the need for the model and develops it to a pre-construction stage. The major steps and processes that must be described for construction of the model to the first development stage are outlined. The first development stage is that of a forest management game. The sources of the data and the initial limitations of the model and the output are given and the subsequent development stages described. / Forestry, Faculty of / Graduate
27 February 2009
M.Ing. / In recent years, many research and development projects have focused on the study of fibre Bragg gratings. Fibre Bragg gratings have been used in the field of sensors, lasers and communications systems. Commercial products that use fibre Bragg gratings are available. On the other hand, in the field of software development, object-oriented programming techniques are also becoming very popular and powerful. The focus of this work is on solving fibre Bragg grating problems by a simulation program with object-oriented programming techniques. For fibre Bragg grating problems, widely used theories and numerical methods such as the coupled-mode theory and the transfer matrix method will be applied in the analysis, modelling and simulation. The coupled-mode theory is a suitable tool for analysis and for obtaining quantitative information about the spectrum of a fibre Bragg grating. The transfer matrix can be used to solve non-uniform fibre Bragg gratings. Two coupled-mode equations can be obtained and simplified by using the weak waveguide approximation. The spectrum characteristics can be obtained by solving these coupled-mode equations. The optical numerical libraries of fibre Bragg gratings have been built by using object-oriented techniques. The code was realized by C++ and Object Pascal language in the Delphi4, C++ Builder4 and Visual C++6 environment. The compiled binary files and the code of the simulation program are available for both the end user and program developer. This simulation program can be used to analyze the performance of sensors and communication systems that use fibre Bragg gratings. Uniform, chirped, apodized, discrete phase shifted and sampled Bragg gratings have already been simulated by using the direct numerical integration method and the transfer matrix method. The reflected and transmitted spectra, time delay and dispersion of fibre Bragg gratings can be obtained by using this simulation program. At the same time, the maximum reflectivity, 3dB-bandwidth and centre wavelength can also be obtained. This thesis consists of three parts. The first part introduces a suitable theory and modelling that have been used to analyze the characteristics of fibre Bragg gratings. Secondly, the codes of the modelling are realized by the suitable programming languages in different development environments. Finally, this simulation program is utilized to analyse real physical problems with fibre Bragg grating applications.
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