In this study, Reometer AR2000 is used to investigate the effect of shear rate on viscosity of emulsion. And a model for the effective viscosity of emulsion is established. Moreover, another model for the hydrodynamic lubrication with binary mixtures of non-Newton fluids is developed. The coupled modified Reynolds are solved by combining the advanced multilevel method with the Newton-Raphson method. The effect of shear rate on lubrication characteristics of hydrodynamic lubrication of emulsion is investigated in cold rolling process. Research results show that the viscosity of emulsion is decreased with increasing the shear rate. Hence,the oil film thickness, oil preasure and oil concentration under hydrodynamic lubrication are increased with decreasing the slide-to roll ratio. Emulsion will be Newton fluid under high shear rate. In the cold rolling process, the emulsion shows the high shear rate, and the elastic deformation of roller and strip are considersd. Hence the end point of plastic zone of strip is moved to oulet zone due to the lubricated zone is increased, so that the film thickness is higher than that for rigid body. When roller radius is increased, the effective elastic modulus and the thickness reduction of strip are decreased, then the lubrication characteristics in cold rolling process are influenced by elastic deformation. When the rolling speed is increased , the inlet film thickness is increased, and the roll torque is slightly increased, but the rolling force and peak preasure are almost not influenced.

Three flexure pivot pad bearings (FPBs) with different preloads are evaluated for use in high performance applications by comparing them to a hybrid hydrostatic bearing (HHB). One application of these bearings is in turbopumps for liquid rocket engines. To evaluate bearing performance, the lift-off speed of the shaft from the bearing surface is experimentally determined. Experimental data of lift-off are collected using a circuit running through the shaft and the designed bearing. Other methods for measuring liftoff speeds were attempted but did not yield consistent results. Water is used as a lubricant to simulate a low viscosity medium. In comparison to load-capacity-based predictions for FPBs, the experimental results showed lower lift-off speeds, higher load capacities, higher eccentricity ratios, and lower attitude angles. The bearings’ predicted load capacity determined lift-off speed predictions, but the experimental results show no clear trend relating lift-off speed to load capacity. This was for a range of running speeds, with the design speed defined as the final speed in a particular test case. At 0.689 bar supply pressure and for a design speed of 3000 rpm, the HHB showed greater load capacities and lower eccentricities than the FPBs, but the FPBs had lower lift-off speeds and attitude angles. In fact, the FPBs in the load-between-pad orientation outperformed the HHB in the load-on-pocket orientation with lower lift-off speeds for the shaft weight-only case. An increased supply pressure lowered the lift-off speeds in the HHB tests. If the load in the bearing application remains relatively small, a FPB could be substituted for an HHB.

The effect of single mode initial conditions at the interface of Rayleigh-Taylor(RT) mixing are experimentally examined utilizing the low Atwood number water channel facility at Texas A&M. The water channel convects two separated stratified flows and unifies them at the end of a splitter plate. The RT instability is attained by convecting a cold stream above a warmer stream. Average density calculations are based on long time average optical measurements. The water channel was modifified with a flapper fin like device at the end of the splitter plate which was actuated by a computer controlled servo motor. Other modifications to the experiment were implemented resulting in reduced uncertainty. The experiment examined five different modes in addition to the baseline: 2 cm, 3 cm, 4 cm, 6 cm, and 8 cm wavelengths. The mixing width growth rates were shown to be dependent on initial conditions. Additionally, it appears that the growth rates commence with terminal velocity and are observed to line up with the baseline case.

In the premise of consideration of age-longed development, it consists of very complicated and challengeable strategies to deal with managerial problem on river basin. This study is focus on the field of Tam Sui River. It is difficult to use numerical simulation in the following situation: The affect of tide on tidal river, the complication of hydrodynamic, and the formation of net-type Tam Sui River by three main confluents. The purpose of establishing hydrodynamic and water quality modeling with STELLA, a software used in systematic dynamic is to provide a valuation benchmark in water quality management. In water system, we want to understand the correlation and mechanism among parameters, and these will help us investigate and analyze the problems in water plan. We also want to make the best choice and decision and gain the biggest efficiency by understanding the characteristics and the contents of water quality. We use one dimension of movement equation in programming STELLA. And we solve hydrodynamuc in different time and different place by using¡unon-linear implicit finite-difference ¡v. In the result of our study, it can not completely simulate the whole situation of turbulence. But in the period of typhoon and flood, the prediction of water line is similar with the real survey in the complexit field. And the one-dimension model is easier to deal with and time-saver than 2-dimension model and 3-dimension model. In the aspect of water quality, we try to apply related mass balance equation in Water Quality Analysis Simulation Program (WASP) to find the chemical reaction among 8 parameters including chlorophyll A, organic phosphorus,inorganic phosphorus,organic nitrogen,ammonia,nitrate,carbonaceous biochemical oxygen demand,dissolved oxygen.After the test and verification, the simulation result meets our expectation and the theoretic value. This model could be extensively applied

The ultimate value of surface roughness and its characteristic for the polishing process was investigated in this thesis. To find out the nature of ultimate surface roughness by means of the hydrodynamic polishing process and can be used for all polishing method. A preliminary mathematical model that was proposed to explain the ultimate surface roughness proceedings and a series of experiments was planed to verify suitable of this model. Starting with the rule for ultimate surface roughness happened. The assumption that abrasive particle at roughness peak and valley machining capability differ less than one atom, the ultimate surface roughness be attained. We can propose the mathematical model of ultimate surface roughness based on this rule and the previous study of hydrodynamic polishing process. Following by useing the computer simulation to help us exploring ultimate surface roughness characteristic and testing experiments fit for the forecasting. Finally, we explain reasons that cause the experiment results not agree with the model anticipation and propose better lubrication condition to polish the optimum surface.

Abstract The main purpose of this study is to develop a hydrodynamic and water quality model using the system dynamic software-STELLA for the tidal river simulations. The model consists of three modules: the hydrodynamic module simulates the water level variation and the dynamic flow conditions in tidal rivers; the transport module simulates the temporal and spatial variations of dissolved matters; and water quality module simulates the bio-chemical reaction processes and the fates of the water quality variables. Water quality module was established from the conceptions of WASP6 with some modifications. Eight state variables are included in the water quality module, i.e. chlorophyll-a, organic phosphorus, inorganic phosphorus, organic nitrogen, ammonia, nitrate, carbonaceous biochemical oxygen demand, and dissolved oxygen. Most the hydrodynamic and water quality models, either imported or domestic developed, were coded in FORTRAN or other conventional programming languages. In this study, the system dynamics software STELLA has been used to construct the model. The study has overcome the difficulty of using STELLA to simulate space continuity and unsteady state condition of tidal river systems. By using STELLA, the environment model can easily be integrated with researches in social-economical studies. The theories and the developments of the model are described in the thesis, the calibration and verification processes of the model using observation data of the Tamshui River system are also describe in detail. The model can be used not only to simulate and to predict the tidal flow, salinity, temperature, and water quality conditions in the Tamshui River, but also be used to evaluate the effects of various water quality purification methods and strategies. Therefore, this model can also assist policymakers to make better decisions on the balancing the economic developments with environmental protections.

The objective of this research is to identify the circulation patterns of the water and sediment fluxes in coastal and estuarine zones, where the shoaling processes correlate with tide generating flow patterns. The research provides a better understanding of the characteristics of spatial and temporal variability of currents. An important deviation from previous research is the inclusion of the baroclinic term, which becomes very important in density driven flows. The understanding of this process provides a basis for determining how the water circulation three-dimensionally controls the hydrodynamics of the system and ultimately transports the suspended and soluble materials due to combined currents and waves. A three-dimensional circulation model is used to calculate the water circulation. The model is based on the three-dimensional (3D) version of Advanced Circulation (AD-CIRC) Hydrodynamic Model with extending the Sediment Transport module. The model is based on the finite element method on unstructured grids. The output of the hydrody-namic model is used to estimate spatial and temporal advections, dispersions and bottom shear stress for the erosion, suspension, deposition and transport of sediment. The model development includes extending the existing three-dimensional (3D) ADCIRC Model with (1) baroclinic forcing term and (2) transport module of suspended and soluble materials. The transport module covers the erosion, material suspension and deposition processes for both cohesive and non-cohesive type sediments. The inclusion of the baroclinic demonstrates the potential of over or underpredicting the total net transport of suspended cohesive sediment under influence of currents. The model provides less than 6% error of theoretical mass conservation for eroded, suspended and deposited sediment material. The inclusion of the baroclinic term in stratified water demonstrates the prevailing longshore sediment transport. It is shown that the model has an application to the transport of the cohesive sediments from the mouth of the Mississippi River along the north shore of the Gulf of Mexico towards and along the Texas coast. The model is also applicable to determine the design erosion thickness of a cap for isolating contaminated dredged material and to evaluate the appro-priate grain size of cap sediments to minimize the erosion.

No description available.

Water and wastewater conveyance research is steeply based in advancements of numerical methods and models. Design engineers need more than refinements in analysis methods to evolve the standards of practice and the related design guidelines. In an effort to improve the design efficiency and operating reliability of pipeline systems, design guidelines have been developed to enfold the various technological advancements and elevate the standard of care used in the pipeline design process. In this respect, the guidelines have been successful. However, design engineers, manufacturers, and owners have developed a level of dependency on the success of the guidelines. The guidelines, which were developed as and are clearly still held to be by the various publishing associations, a minimum standard of care, have become the default standard of care. Such statements are, of course, gross generalizations, but this thesis is dedicated to move the standard of care forward through an integrated design approach that provides a roadmap to inter-relate the independent design guidelines into a composite design approach based on hydrodynamic loading. Hydrodynamic loading introduces of a temporal parameter into the design process. With the temporal parameter this work demonstrates how the consideration of both the frequency and the influence of acceleration head on the magnitude of the hydraulic loading can be used to integrate and evolve the individual component designs into a more efficient, cost effective, reliable composite design result. With a temporal parameter present in design, many opportunities present themselves to advance the current design procedures outlined in the present design guidelines. This thesis identifies some of the present shortcomings found in the modern pipeline and appurtenance design standards and introduces a recommended path forward. Specific changes to the present standards are proposed in this work and a unique analysis procedure to identify the failure potential of cement mortar lining has been developed. Introducing the integrated design approach will allow for a significant evolution to the present standard of practice in water and wastewater conveyance system designs.

Water and wastewater conveyance research is steeply based in advancements of numerical methods and models. Design engineers need more than refinements in analysis methods to evolve the standards of practice and the related design guidelines. In an effort to improve the design efficiency and operating reliability of pipeline systems, design guidelines have been developed to enfold the various technological advancements and elevate the standard of care used in the pipeline design process. In this respect, the guidelines have been successful. However, design engineers, manufacturers, and owners have developed a level of dependency on the success of the guidelines. The guidelines, which were developed as and are clearly still held to be by the various publishing associations, a minimum standard of care, have become the default standard of care. Such statements are, of course, gross generalizations, but this thesis is dedicated to move the standard of care forward through an integrated design approach that provides a roadmap to inter-relate the independent design guidelines into a composite design approach based on hydrodynamic loading. Hydrodynamic loading introduces of a temporal parameter into the design process. With the temporal parameter this work demonstrates how the consideration of both the frequency and the influence of acceleration head on the magnitude of the hydraulic loading can be used to integrate and evolve the individual component designs into a more efficient, cost effective, reliable composite design result. With a temporal parameter present in design, many opportunities present themselves to advance the current design procedures outlined in the present design guidelines. This thesis identifies some of the present shortcomings found in the modern pipeline and appurtenance design standards and introduces a recommended path forward. Specific changes to the present standards are proposed in this work and a unique analysis procedure to identify the failure potential of cement mortar lining has been developed. Introducing the integrated design approach will allow for a significant evolution to the present standard of practice in water and wastewater conveyance system designs.