During the summers of 1973 anrd 1974 processes and related responses operating on a small High Arctic sandur (basin area 91 km²) were studied. Several aspects related to the sandur were investigated, including the hydrologic regime of surface runoff, channel hydraulic conditions, sediment transport, and the morphology of the channels and sandur surface. Summer climatic conditions strongly affected surface runoff due to their influence on snowmelt, qlacial melt, and summer precipitation, There was a noticeable diurnal rhythm in streamflow in response to snowmelt and glacial melt. The influences of ice blockcage effects on streamflow were also observable. A shallow active layer resulted in a rapid response of surface runoff to snowmelt, glacial melt, and rainfall sources. These aspects of the hydrologic regime strongly affected the hydraulic conditions of the streams. The main hydraulic adjustment was produced by changes in velocity which led to rapid changes in flow resistance and resulted in large variations in the rates of sediment transport. Estimates of the stream load in the 1974 summer confirmed that the bulk of the sediment was carried as bedload. Channel bar forms which reflected hydraulic conditions changed considerably over a summer period. On a long term basis, the form of the channel longitudinal profile indicated an adjustment to downstream hydraulic conditions while the surface morphology and sediment distribution over the sandur revealerl the two-dimensional variations in channel processes. / Thesis / Bachelor of Arts (BA)

Semi-active dampers utilizing various working principles have been developed for a variety of vehicles. These semi-active dampers have been designed to resolve the ride and handling compromise associated with conventional passive dampers, and increase vehicle stability. This thesis briefly reviews existing semi-active damper designs, including but not limited to MR dampers, before presenting two new prototype semi-active hydraulic dampers. Both prototype dampers are designed to provide a large force range while maintaining easily controllable valve characteristics. The first of these dampers served primarily as a proof of concept and a means of understanding the dynamics of a disc valve housed inside the main piston. The valve design is presented, along with other information concerning the fabrication of the Initial Prototype damper. Test results are presented and analyzed, and a second iteration of the valve is designed. The Final Prototype damper is a scaled up version of the initial design, with refinements made in piston geometry, internal disc profile, and dynamic seals. This large force range damper is tested and results are compared with existing MR dampers. The Final Prototype damper provides a significantly larger force range when compared with typical MR dampers. Finally, to conclude this research, the vehicle dynamics implications of the Final Prototype damper are discussed and recommendations for further study are made. / Master of Science

A theoretical model and associated computer program are developed to compute hydrodynamic interaction forces and moments on passing ships in a shallow asymmetric canal, by applying generalized Lagally's theorem. Steady lift force on the ships are estimated following standard slenderbody approach. Passing ships are assumed to travel at constant speeds, parallel to the canal walls. Ships are assumed to be slender, the fluid is ideal and wave making effects are ignored. Numerical calculations for several passing cases show good agreement with existing model test results. / M.S.

In order to protect gas turbine blades from hot gases exiting the combustor, several intricate external and internal cooling concepts are employed. High pressure stage gas turbine blades feature serpentine passages where rib turbulators are installed to enhance heat transfer between the relatively colder air bled off from the compressor and the hot internal walls. Most of the prior studies have been restricted to Reynolds number of 90000 and several studies have been carried out to determine geometrically optimized parameters for achieving high levels of heat transfer in this range of Reynolds number. However, for land-based power generation gas turbines, the Reynolds numbers are significantly high and vary between 105 and 106. Present study is targeted towards these high Reynolds numbers where traditional rib turbulator shapes and prescribed optimum geometrical parameters have been investigated experimentally. A steady-state liquid crystal thermography technique is employed for measurement of detailed heat transfer coefficient. Five different rib configurations, viz., 45 deg., V-shaped, inverse V-shaped, W-shaped and M-shaped have been investigated for Reynolds numbers ranging from 150,000 to 400,000. The ribs were installed on two opposite walls of a straight duct with aspect ratio of unity. For very high Reynolds numbers, the heat transfer enhancement levels for different rib shapes varied between 1.3 and 1.7 and the thermal hydraulic performance was found to be less than unity. / Master of Science / Gas turbine blades operate in hot gases exiting from combustor. The temperature of the hot gas is much higher than the melting point of blades material. To protect gas turbine blades several intricate external and internal cooling technique have been applied. Inside the blades, impingement cooling, rib turbulators cooling and pin fins cooling technique are applied in the leading edge, central body and trailing edge, respectively. At the central body serpentine passage was manufactured where rib turbulators are installed to enhance heat transfer between the relatively colder air bled off from the compressor and the hot internal walls. This is attributed to the colder air’s boundary layer is tripped by the rib turbulators enhance the flow turbulence. All the previous works are based on lower Reynolds number (under 90000) which always happens in aircraft gas turbine engine. In land based gas turbine the Reynolds numbers of cooling air are significantly high and vary between 10⁵ and 10⁶ . Present study is targeted towards these high Reynolds numbers where traditional rib turbulator shapes and prescribed optimum geometrical parameters have been investigated experimentally. Five different rib configurations, viz., 45 deg., V-shaped, inverse V-shaped, W-shaped and M-shaped have been investigated for Reynolds numbers ranging from 150,000 to 400,000. For very high Reynolds numbers, the heat transfer enhancement levels for different rib shapes varied between 1.3 and 1.7 and the thermal hydraulic performance was found to be less than unity. It’s a caution to turbine hot gas path designers, particularly for the cases where rib designs for aircrafts are used in land based power generationgas turbines

The use of draft tubes with annular injection was investigated with respect to low-head applications. A numerical model was developed and refined to fit the data from two laboratory test models. The latter model was a laboratory scale hydropower system which demonstrated 20-31 per cent head augmentation under various conditions. The numerical model was used to generate performance maps of full scale, low-head systems in the range from 200 to 500 kW. The performance maps were then used in a system modeling program to evaluate the system performance, cost and cavitation characteristics. The draft tube ejector system was found to reduce the system cost/kW by 2-10 per cent when compared to a conventional system with the same gross head and total flow rate. This was accomplished by using smaller, less expensive turbines which utilize excess flow in draft tube ejectors to increase the effective head across the turbine. The resulting reduction in system cost was found to exceed the corresponding reduction in capacity. The use of draft tube ejectors was found to require slightly lower turbine settings due to increased cavitation risk. / Master of Science

Inflatable dams are flexible membrane structures, pressurized with either air, water, or both, which have been used in recent years as a means of temporarily impounding water. A number of procedures have been developed to investigate the static behavior of the dams, but the dynamic behavior has been largely neglected. The few studies that have been done on dynamic behavior have used the simplifying assumption that the weight of the membrane was negligible. In this study, equations of equilibrium and equations of motion were derived for an air inflated dam impounding no water, but loaded with its own membrane weight. It was assumed that the effect of membrane extensibility is negligible in the analysis. Derivatives required in the equations of motion were approximated using finite difference equations. Computer programs were written to find solutions for the eigenvalues and eigenvectors of the equations of motion. The computer program plotted the mode shapes of vibration associated with the four lowest eigenvalues, as well as the static shape of the dam. The eigenvalues obtained were the square of the frequencies of the system, so the effects of a series of membrane weights on the frequencies of dams of various base lengths could be analyzed. / M.S.

This thesis consists of an experimental study of the velocity distribution in tranquil, stable tumbling and rapid flow regimes in a steep rectangular channel with artificial roughness elements. Four shapes of roughness elements, rectangular, parallelogram, triangular, and semi-circular, were used. Effects on velocity distribution due to variations in discharge, flume slope and roughness geometry were studied for each shape of roughness element. The applicability of logarithmic law was examined and the inflection points in tranquil and rapid flow regime were studied. Also the velocity coefficients in tumbling regime were studied. The findings were confirmed through the analysis of data taken from project 405 of the Civil Engineering Department. A review of literature on this subject and a bibliography are included. / Master of Science

In some U.S. coal mining operations, the available production capacity is limited by existing mechanical hoisting systems rather than mining methods. This thesis presents a research effort to supplement existing mechanical hoisting with a hydraulic hoisting system. The purpose is to overcome limitations of the mechanical hoisting system in order to attain the maximum production capacity of the coal mine. The research objectives are: to conduct a parametric study of hydraulic hoisting systems combined with mechanical hoisting methods in different mining situations; to develop models, functions, and indices for use in practical design, and; to develop procedures for estimating the technical and economic factors of supplementary hydraulic hoisting systems. This research is expected to offer an objective approach which can increase the production capacity and reduce operating costs of coal mines. / Master of Science

The height of an overflow dam must be designed low enough to prevent the reservoir water level from exceeding a flood plain during flooding conditions. Because of this constraint, much of the available water storage area is wasted and the available pressure head for power generation will be less than maximum during normal conditions. Crest control gates alleviate this problem by providing a variable spillway height. The Flash Gate Board is a passive automatic crest control gate. Its purpose is to regulate flood water while providing increased water pressure for power generation or for additional water storage for a municipality. The governing equations for the Flash Gate Board system are derived and used to formulate models of the system. Computer simulations are used to examine the system response in a variety of operating conditions. The results of these simulations are presented and discussed. The results include an investigation which developed an optimum gate height to maximize the potential of the Flash Gate Board. An experimental model was developed to verify analytical results and to provide additional insight. Conclusions from the study, recommendations for future work, and modifications for a trouble-free design are discussed. / Master of Science

Surface water-groundwater interaction can provide various stream functions including temperature regulation, nutrient cycling, pollutant attenuation, and habitat creation. However previous literature is divided on the extent and conditions of these benefits. This dissertation has explored the dominance of hydraulic conductivity (K) on hyporheic hydraulics and implications to hyporheic zone functions through a series of modeling studies and field experiments. Computational Fluid Dynamics (CFD) software was used to model the effect of varying K on weir-induced hyporheic exchange hydraulics and heat transport. Fundamental shifts in hydraulics and temperature dynamics occurred at threshold K's. Surface water began noticeably sinking into the bed above a threshold of K=10-3 m/s and inertial forces caused deviation from Darcy's Law. The heat transport model indicated net downstream surface water cooling from weir-induced exchange was maximized by maximizing K (flow-limited function) and thermal heterogeneity increased with K, particularly above K=10-5 m/s. Results suggest that using CFD to predict surface water-groundwater interaction may be important to accurately predict hyporheic hydraulics and functions dependent on flow-rate or residence time. The importance of macropores to hyporheic transport through meander bends was explored. Transport velocities, hydraulic head gradients, and solute transport rates through the meander bend were increased by macropores. Results indicate that macropores can dictate solute or pollutant transport through meander bends and in the hyporheic zone, which in turn may influence biogeochemical cycling and pollutant attenuation. Surface-connected macropores along streams were studied as hydrologically important subsurface heterogeneities for surface water-groundwater interaction. Macropores were common geomorphic features in the Appalachian province of southwestern Virginia, and were inundated during storm events over a one-year period. Banks with macropores experienced increased hydraulic head fluctuations, temperature fluctuations, and K. Macropores increased bank storage rates and solute transport between the channel and riparian groundwater zones, which in turn may influence biogeochemical cycling, pollutant attenuation, and hyporheic habitat. Macropores may be important to hyporheic flow and solute transport in a wide range of conditions and may broaden the portion of the landscape in which hyporheic exchange is important. Future work is needed to further assess the impacts of macropores on hyporheic functions and explore new methods to map and quantify macropore geometries and inter-connectivity. / Ph. D.