A General-Purpose Finite-Difference Code for Solving Steady-State Three-Dimensional Fluid Flow and Heat Transfer Problems

A general purpose FORTRAN code is described for the computations of three-dimensional steady heat transfer and fluid flow in rectangular geometries. The code is designed to handle combined conductionconvection problems within domains comprising of both solid and fluid regions. This is accomplished through the use of the harmonic mean formulation for evaluating interface diffusivities. A control volume formulation is used to discretize the governing equations for the dependent variables in the primitive form. The velocity-pressure coupling is handled by the SIMPLER algorithm. The iterative solution scheme employs the tri-diagonal matrix algorithm of Thomas. A sample example of three-dimensional natural convection in a rectangular enclosure is used to validate the code against existing numerical solutions.Naval Weapons Support Center, Crane, Indianahttp://archive.org/details/generalpurposefi00sathNWSC, CraneNAApproved for public release; distribution is unlimited

AMPHIB: a users manual

A general purpose three-dimensional code (AMPHIB) that solves electronic cooling problems is documented. In its present structure, the code is set up for computations in liquid immersion cooling of an m by n array of chips embedded in a substrate in a three-dimensional rectangular enclosure. Nevertheless, it can be modified to solve problems in forced, mixed and natural convection for a wide range of boundary conditions. The subroutines and the input are described in detail. A listing of the code and sample example problems are also included.http://archive.org/details/amphibusersmanua00mukuApproved for public release; distribution is unlimited

Regional variation in pig farmer awareness and actions regarding Japanese encephalitis in Nepal : implications for public health education

The objective was to explore regional variations in farmer awareness and actions towards Japanese Encephalitis (JE) in Nepal; the association of awareness and actions with farm and farmer variables; and the implications for public health education and extension services. Social factors such as literacy, gender, and cultural practices were associated with farmer attitudes, knowledge and practices for JE control. The low uptake of vaccine and lack of infrastructure or financial capacity to house pigs adequately suggest that farmer personal protection should be a priority for education. JE is a mosquito-borne zoonotic disease with pigs as the amplifying hosts

Resume of Yogendra Joshi, 1988-09

Naval Postgraduate School Faculty Resum

Thermal Modeling of Gas Tungsten Arc Welding Process with Nonaxisymmetric Boundary Conditions

The article of record as published may be found at http://dx.doi.org/10.1080/10407789508913715A numerical study of three-dimensional heat transfer and fluid flow in a moving gas tungsten arc welding (GTAW) process is performed by considering nonaxisymmetric boundary conditions. The current density distribution and the resulting Lorentz force field are evaluated by numerically solving Maxwell's equations in the domain of the workpiece. The numerical modeling of the melting/solidification process is done by appropriately applying the enthalpy-porosity approach to the GTAW process. Numerical computations of the heat transfer and flow characteristics are carried out by including the effects of buoyancy, surface tension, and electromagnetic forces. The weld-pool dynamics is found to be strongly dependent on the relative locations of the clamp and electrode.National Research CouncilNational Science Foundation CBT-880897

TRANSIENT NATURAL CONVECTION FLOWS AND NATURAL CONVECTION FLOWS IN POROUS MEDIA

An investigation of transient natural convection flows adjacent to a vertical surface and an analysis of external natural convection flows in porous media is presented. In Chapter 1, experimental results and interpretations are given for transient natural convection adjacent to a suddenly heated flat vertical surface in water. Flows were visualized and velocity and temperature measurements made at various downstream locations, after imposing a uniform internal energy generation rate within the surface. Laminar flow persisted into steady state, for short downstream distances. Further up, the flow became turbulent during the transient. Relaminarization at later times occurred only for lower flux inputs. In Chapter 2, vertical transient natural convection response following a change in surface heating has been determined. For short times, closed form solutions for the fluid velocity and temperature have been obtained, for all values of the Prandtl number. Thereafter, the transient boundary layer equations are solved numerically, for water, Pr = 6.2. Experiments verify both the short time solutions and the finite difference computations. Short time transient response of a yet different kind is obtained in Chapter 3. The ambient medium is cold water, giving rise to a nonlinear density variation with temperature. Closed form solutions for flow velocity have been obtained for two important surface conditions. These are: (a) an initial step in the surface energy generation rate and (b) a step in the surface temperature. Transient and steady flows in cold water are experimentally investigated in Chapter 4. The range of ambient temperatures studied is, 1.1 (LESSTHEQ) t(,(INFIN)) (LESSTHEQ) 6.9(DEGREES)C, for heating rates, q(,(INFIN))\u27\u27, in the range 587-1870 W/m(\u272). Flows were visualized and local surface temperatures measured. Details of flow and transport evolution starting from quiescence are studied. Chapter 5 considers a slightly different flow circumstance, where the ambient is a fluid saturated porous medium. Higher order corrections to the steady boundary layer solutions have been obtained for three flows. These are: (a) an isothermal surface, (b) a uniform flux surface and (c) a line plume. Effects of a externally imposed free stream on transport are investigated for (a)

TRANSIENT NATURAL CONVECTION FLOWS AND NATURAL CONVECTION FLOWS IN POROUS MEDIA

An investigation of transient natural convection flows adjacent to a vertical surface and an analysis of external natural convection flows in porous media is presented. In Chapter 1, experimental results and interpretations are given for transient natural convection adjacent to a suddenly heated flat vertical surface in water. Flows were visualized and velocity and temperature measurements made at various downstream locations, after imposing a uniform internal energy generation rate within the surface. Laminar flow persisted into steady state, for short downstream distances. Further up, the flow became turbulent during the transient. Relaminarization at later times occurred only for lower flux inputs. In Chapter 2, vertical transient natural convection response following a change in surface heating has been determined. For short times, closed form solutions for the fluid velocity and temperature have been obtained, for all values of the Prandtl number. Thereafter, the transient boundary layer equations are solved numerically, for water, Pr = 6.2. Experiments verify both the short time solutions and the finite difference computations. Short time transient response of a yet different kind is obtained in Chapter 3. The ambient medium is cold water, giving rise to a nonlinear density variation with temperature. Closed form solutions for flow velocity have been obtained for two important surface conditions. These are: (a) an initial step in the surface energy generation rate and (b) a step in the surface temperature. Transient and steady flows in cold water are experimentally investigated in Chapter 4. The range of ambient temperatures studied is, 1.1 (LESSTHEQ) t(,(INFIN)) (LESSTHEQ) 6.9(DEGREES)C, for heating rates, q(,(INFIN))\u27\u27, in the range 587-1870 W/m(\u272). Flows were visualized and local surface temperatures measured. Details of flow and transport evolution starting from quiescence are studied. Chapter 5 considers a slightly different flow circumstance, where the ambient is a fluid saturated porous medium. Higher order corrections to the steady boundary layer solutions have been obtained for three flows. These are: (a) an isothermal surface, (b) a uniform flux surface and (c) a line plume. Effects of a externally imposed free stream on transport are investigated for (a)

Numerical modelling of drawbeads for forming of aluminium alloys

Drawbeads control the flow of material into the die cavity during pressing operations. The tribological and forming properties of aluminium necessitate specific frictional and drawbead geometry requirements that are different from those established over many years for steels. Academic research on this topic is limited, requiring industry to rely on trial and error methods to determine the coefficient of friction and drawbead geometry. This research project focused on developing an innovative, scientific and holistic methodology to determine the optimum drawbead geometry and an appropriate coefficient of friction value to be used in forming feasibility simulations for aluminium panels. Special attention was given to the ease with which this research could be implemented in an industrial environment. Hence, extensive experiments to gather material properties such as plane strain and pure shear tests, complex material models, or optimisation models based on artificial neural networks (ANN), and non-linear friction models were avoided. Three approaches identified in the literature for designing drawbeads, namely, experimental, analytical and numerical modelling were investigated to test the underlying assumptions, strengths and limits of each. For example, analytical models assumed symmetric material flow passing over the drawbeads, which in reality does not occur. Based on these findings a systematic, hybrid approach has been developed which uses a combination of physical drawbead tests and numerical modelling, to determine the coefficient of friction which is then used to obtain the drawbead restraining force. Using a novel criterion, different drawbead geometry conditions have been ranked to aid selection of an optimised drawbead geometry. The optimised drawbead geometry obtained from the hybrid approach was validated by stamping of rectangular pans. The rectangular pan, when stamped using the optimised geometry obtained from the hybrid approach, did not show defects such as severe thinning and wrinkles. The numerical stamping model with geometric drawbead predicted the punch force with a 4.5% error, thinning with a 5% error and draw-in with an 8% error. An innovative hybrid approach has been proposed which is capable of accurately predicting the coefficient of friction, the drawbead restraining force and the drawbead geometry. The same coefficient of friction and the drawbead geometry when used in the forming simulation accurately predicted the punch force, thinning and draw-in. As a direct application of innovation, Jaguar Land Rover can use the novel criteria for selecting the drawbead geometry to use effectively the drawbead geometry generation feature in the commercial sheet metal forming software package during forming feasibility simulations. The hybrid approach can potentially save 34% of the die tryout time and provide average cost savings of £34,400 per die set per tryout attempt

Energy efficient thermal management of data centers

Energy Efficient Thermal Management of Data Centers examines energy flow in today's data centers. Particular focus is given to the state-of-the-art thermal management and thermal design approaches now being implemented across the multiple length scales involved. The impact of future trends in information technology hardware, and emerging software paradigms such as cloud computing and virtualization, on thermal management are also addressed. The book explores computational and experimental characterization approaches for determining temperature and air flow patterns within data centers. Thermodynamic analyses using the second law to improve energy efficiency are introduced and used in proposing improvements in cooling methodologies. Reduced-order modeling and robust multi-objective design of next generation data centers are discussed. This book also: Provides in-depth treatment of energy efficiency ideas based on  fundamental heat transfer, fluid mechanics, thermodynamics, controls, and computer science Focuses on multiple broad approaches that can yield significant improvements in data center energy efficiency Contains comprehensive coverage of all aspects of thermal management in data centers Features an introduction to real-time allocation of computing loads in virtualized environments and cloud computing Energy Efficient Thermal Management of Data Centers is an essential book for academic researchers working in thermal design, power delivery and cloud computing, as well as engineers working in critical facility design,cooling equipment and IT manufacturing