This study shows how a cost-effective hydraulic tomography survey (HTS) and the associated data estimator can be used to characterize flow and transport in heterogeneous aquifers. The HTS is an improved field hydraulic test that accounts for responses of hydraulic stresses caused by pumping or injection events at different locations of an aquifer. A sequential data assimilation method based on ...

It is common for subsurface flow to transition between porous and fractured media. Two examples include vertical infiltration of precipitation through a permeable soil overlying a fractured bedrock, and horizontal ground water flow through a combination of porous and fractured geologic units. A reduction in flow or flow impedance may occur across these interfaces caused by head losses associate...

Estimation of soil hydraulic and solute transport parameters is important to provide input parameters for numerical models simulating transient water ̄ow and solute transport in the vadose zone. The Levenberg±Marquardt optimization algorithm in combination with the HYDRUS-1D numerical code was used to inversely estimate unsaturated soil-hydraulic and solute transport parameters from transient m...

Pumped storage plants (PSP) must switch frequently between various working conditions. Moreover, PSPs can fall easily into an S-shaped zone under low water head conditions, especially during back-to-back starting (BTBS), which reduces the stability and safety of unit operation. In this paper, a nonlinear PSP model for BTBS is established by combining electrical subsystem with refined hydraulic-...

This paper presents a detailed model of a novel electropneumatic valve actuator for both engine intake and exhaust valves. The valve actuator’s main function is to provide variable valve timing and variable lift capabilities in an internal combustion engine. The pneumatic actuation is used to open the valve and the hydraulic latch mechanism is used to hold the valve open and to reduce valve sea...

[1] A new technology, hydraulic/partitioning tracer tomography (HPTT), is proposed to survey spatial distributions of hydraulic properties and dense nonaqueous phase liquids (DNAPLs) in the subsurface. HPTT is nothing more than a set of multiple hydraulic/ partitioning tracer tests and synthesis of all the tests to map the spatial distributions. It involves injection of water at one borehole in...

We present a semi-analytical solution for the transient streaming potential response of a confined aquifer to pumping at a constant rate through a fully-penetrating line sink. Confined aquifer flow is assumed to occur without fluid leakage from the confining units and is thus described by the solution of Theis (1935). The confining units, which are typically more electrically conductive than th...

Sediment erosion not only reduces efficiency and life of hydropower turbines but also causes problems in operation and maintenance. Several factors are responsible for this erosion in hydro turbine components. This paper presents the sediment erosion types in hydraulic turbines and their components based upon an extensive literature review and the field observation at Cahua hydropower plant, Pe...

Centrifugal pumps are designed to have their BEP (Best Efficiency Point) for a given flow rate, hydraulic head, and speed. In the design phase, those parameters combined into dimensionless specific speed used define geometry of pump. this paper, downsized centrifugal pump has been high efficiency at very speeds (10000 – 15000 RPM), as requested by cooling circuit an engine motorsport racing app...

Abstract We summarize the basic principles of, and governing equations for, groundwater flow transport. Topics covered include concepts of pressure hydraulic head, Darcy’s law, permeability, storage. compare saturated unsaturated flow. provide an introduction to heat solute