Solution of one dimensional transient flow in composite aquifers using stehfest algorithm

Download
2010
Bakar, Ürün
In this study, piezometric heads in a composite aquifer composed of an alluvial deposit having a width adjacent to a semi-infinite fractured rock are determined. One dimensional transient flow induced by a constant discharge pumping rate from a stream intersecting alluvial part of the aquifer is considered. Parts of the aquifer are homogeneous andisotropic. Equations of flow, initial and boundary conditions are converted to dimensionless forms for graphical presentation and the interpretation of results independent of discharge and head inputs specific to the problem. Equations are solved first in Laplace domain and Laplace domain solutions are inverted numerically to real time domain by utilizing Stehfest algorithm.For this purpose, a set of subroutines in VBA Excel are developed. This procedure is verified by application of code to flow in semi-infinite homogeneous aquifer under constant discharge for which analytical solution is available in literature. VBA codes are also developed for two special cases of finite aquifer with impervious and with recharge boundary on the right hand side. Results of composite aquifer solutions with extreme tranmissivity values are compared with these two cases for verification of methodology and sensivity of results.

Suggestions

Determination of hydraulic parameters of semi-infinite aquifers using Marquardt algorithm
Taşkan, Cüneyt; Önder, Halil; Department of Civil Engineering (2004)
In this study, transmissivity and storage coefficient of a semi-infinite, confined, homogeneous and isotropic aquifer, where the flow is one-dimensional and linear, are determined using Marquardt algorithm, considering two independent cases: constant drawdown in the adjacent stream; or constant discharge from the aquifer due to pumping at a constant rate. In the first case piezometric head and discharge measurements are utilized. Hydraulic diffusivity, which is the ratio of transmissivity to storage coeffic...
Forced hydraulic jump on artificially roughened beds
Şimşek, Çağdaş; Tokyay, Nuray; Department of Civil Engineering (2006)
In the scope of the study, prismatic roughness elements with different longitudinal spacing and arrangements have been tested in a rectangular flume in order to reveal their effects on fundamental characteristics of a hydraulic jump. Two basic roughness types with altering arrangements have been tested. Roughness elements of the first type extends through the channel width against the flow with varying length and pitch ratios for different arrangements. The second type is of staggered essence and produced b...
The effect of prismatic ruoghness elements on hydraulic jump
Evcimen, Taylan Ulaş; Tokyay, Nuray; Department of Civil Engineering (2005)
The objective of this study is to determine the effect of different roughness types and arrangements on hydraulic jump characteristics in a rectangular channel. Three different types of roughness were used along experiments. All of them had rectangular prism shapes and that were placed normal to the flow direction. To avoid cavitation, height of roughness elements were arranged according to level of the channel inlet, so that the crests of roughness elements would not be protruding into the flow. The effect...
Simulation of surface waves generated by a rapid rise of a block at the sea bottom
Şenol, Nalan; Aydın, İsmail; Department of Civil Engineering (2005)
A mathematical model is developed for investigating time dependent surface deformations of a hydrostatic water volume, when it is subjected to a sudden partial rise of the sea bottom. In the model, 2-dimensional, compressible, and viscous Navier-Stokes equations are solved by Marker and Cell (MAC) method. Variable mesh size in both horizontal and vertical directions with a staggered grid arrangement is used. Limited compressibility model is utilized for pressure. Various computational tests are done for the...
Formation of air-entraining vortices at horizontal water intakes /
Zaloğlu, Cihan; Göğüş, Mustafa; Department of Civil Engineering (2014)
The goal of this study is to estimate the critical submergence depths of horizontal water intakes that have symmetrical and asymmetrical approach flow conditions by using empirical equations. Therefore a series of experiments were performed in a reservoir-pipe system dominated by gravity and controlled by a valve. On account of adjustable lateral walls, symmetrical and asymmetrical flow conditions were created at various Froude numbers. For a wide range of discharges and for three different pipe diameters, ...
Citation Formats
Ü. Bakar, “Solution of one dimensional transient flow in composite aquifers using stehfest algorithm,” M.S. - Master of Science, Middle East Technical University, 2010.