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Develop a numerical model to evaluate furrow irrigation performance
| dc.creator | Jnad, Ihab | |
| dc.date.accessioned | 2012-06-07T22:45:06Z | |
| dc.date.available | 2012-06-07T22:45:06Z | |
| dc.date.created | 1996 | |
| dc.date.issued | 1996 | |
| dc.identifier.uri | https://hdl.handle.net/1969.1/ETD-TAMU-1996-THESIS-J533 | |
| dc.description | Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item. | en |
| dc.description | Includes bibliographical references. | en |
| dc.description | Issued also on microfiche from Lange Micrographics. | en |
| dc.description.abstract | A numerical model to evaluate furrow irrigation performance was developed and tested. The MacCormack scheme, which is a second order accurate explicit finite difference method, was utilized to solve the complete form of the continuity and momentum equations for unsteady gradually varied flow in a furrow. On the furrow boundaries, the method of characteristics in conjunction with the boundary conditions was utilized to solve the furrow flow equation. The model was tested by comparing predicted advance times, recession times, and outflow hydrographs with field data. Field data were collected from four different locations in Texas and Colorado. The measured data included a variety of soil types, flowrates, furrow lengths, and times of cutoff. The modified Kostiakov equation was utilized to describe the infiltration process. The model accurately predicted advance time. In three of the data sets the average absolute error of advance time was less than 5%. The model did a reasonably good job of predicting recession times. The shape of predicted outflow hydrographs matched the shape of observed outflow hydrographs. The predicted peak flow rates were in good agreement with observed peak flowrates. The average relative absolute error of predicted total outflow volume was less than 7%. Irrigation uniformity, root zone efficiency, and percent deep percolation were slightly sensitive to variations in furrow bottom slope and surface roughness while the pattern distribution efficiency and percent runoff volume were moderately sensitive. In the analysis of model sensitivity to variations in the modified Kostiakov infiltration equation coefficients, the advance time and runoff volume were moderately sensitive to a', and highly sensitive to k'and f,,. Irrigation performance was more sensitive to f,, than to a'or k'. The modified Kostiakov infiltration equation described the infiltration process during irrigation more accurately than the Kostiakov infiltration equation. | en |
| dc.format.medium | electronic | en |
| dc.format.mimetype | application/pdf | |
| dc.language.iso | en_US | |
| dc.publisher | Texas A&M University | |
| dc.rights | This thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries in 2008. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use. | en |
| dc.subject | civil engineering. | en |
| dc.subject | Major civil engineering. | en |
| dc.title | Develop a numerical model to evaluate furrow irrigation performance | en |
| dc.type | Thesis | en |
| thesis.degree.discipline | civil engineering | en |
| thesis.degree.name | M.S. | en |
| thesis.degree.level | Masters | en |
| dc.type.genre | thesis | en |
| dc.type.material | text | en |
| dc.format.digitalOrigin | reformatted digital | en |
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