الفهرس | Only 14 pages are availabe for public view |
Abstract In general, wells partially penetrate the entire thickness of the aquifer. If the length of water entry (or the screen interval) in a well is less than the entire thickness of the aquifer, the well is called partially penetrating well. The influence of partial penetration of a well becomes less pronounced as the ratio between the screen interval and the aquifer thickness increases. The groundwater flow to or from a partially penetrating well is three dimensional. As a result, the drawdown around pumping and observation wells is dependant on their screened lengths and location along the thickness of the aquifer. A few number of computer programs appears to provide solutions for partially penetrating well, but, none of these programs deals with all equations of fully/partially penetrating wells, for all kinds ofaquifers, and for all flow conditions. Moreover, the free access programs are extremely limited. The main objective of this study is to develop an analytical program, using Matlab program, for solving the analytical equations of groundwater·wells. The equations are developed by Theis, Hantush, Jacob, and Neuman covering confined aquifers, semi-confined aquifers, and unconfined ones. The program saves the time and effort of calculations for solving the complicated analytical equations. The program is a visual interacting one, but this interface is made using Matlab program, with the advantage of reducing the probability of error in entering data. The solutions simulate different ·conditions of fully/ partially penetrating wells in steady and unsteady conditions. More understanding of the wells hydraulic’s has been achieved through using the program. A group of dimensionless curves are prepared for fine , medium, and coarse sand, to predict the increase in drawdown or the decrease in discharge due to the wells partial penetration. Some specific problems, concerning wells hydraulics, are investigated. The additional drawdown due to partial penetration is also addressed. The effective aquifer thickness in case of well partial penetration is identified. The optimum screen length for maximum well yield, is also predicted. The radius of influence of wells, is finally determined by the program. |