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Albert J. Clemmens
United States Department of Agriculture
150Publications
22H-index
2,134Citations
Publications 150
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AbstractA variety of methods are in use for the design of controllers for adjusting canal gate positions to maintain a constant water level immediately upstream from check gates. These methods generally rely on a series of tests on the water level’s response to changes in canal gate position or flow, either by simulation or on the canal itself. This paper presents a method for tuning these controllers based on wave celerity through use of the integrator delay zero (IDZ) model. These equations ca...
AbstractThe SRFR program is a modeling system for surface irrigation. It is a central component of WinSRFR, a software package for the hydraulic analysis of surface irrigation systems. SRFR solves simplified versions of the equations of unsteady open channel flow coupled to a user-selected infiltration model. SRFR was reprogrammed using a modern object-oriented architecture with the objective of facilitating its continued development and, thus, the addition of new modeling options and functional...
This paper presents an internally coupled flow and solute transport model for free-draining irrigation furrows. Furrow hydraulics is simulated with a numerical zero-inertia model and solute transport is computed with a numerical cross-section averaged advection-dispersion model. A procedure for integrating the furrow volumetric cumulative intake integral in the context of a hydraulic model is presented. Two hydraulic and solute transport data sets collected in sloping free-draining test furrows ...
Abstract Volume-balance models of surface irrigation calculate the infiltrated volume at a given time as a product of the stream length, upstream infiltration, and shape factors. The best-known expression of this type was derived by combining the Lewis-Milne equation with empirical power-law expressions for infiltration and advance as functions of time. This expression results in systematic errors that are not well understood by users of volume-balance methods. This article examines those errors...
Abstract This article reviews procedures for estimating surface storage in surface irrigation volume balance calculations. Those procedures are based on the assumption of a power law relationship for flow depth as a function of distance along the stream. The analysis uses zero-inertia simulation and a system of dimensionless variables to examine how the depth profile varies as a function of hydraulic conditions when infiltration is given by the empirical extended Kostiakov equation. Alternatives...
Advanced mathematical models of surface irrigation use the equations of motion applied to a series of cells comprising the surface stream and an infiltration profile. In the simulation, a mass balance must be preserved among the inflow, surface stream, infiltrated profile, and runoff volumes. The shapes of the profiles are not known a priori, yet the curvature of the element boundaries influences the calculation of the volume contained therein, especially near the front of the irrigation stream....
The operation of main irrigation canals is complicated in situations in which the operator does not have full control over the canal inflow, or in which there are very long transmission distances from the point of supply, or both. Experienced operators are able to control the canal, but often supply errors are simply passed downstream, thus creating problems further down the system. In previous work, the writer showed that it is important to contain such errors and not let them pass downstream. ...
The integrator-delay (ID) model is commonly used to model canal pools that do not exhibit resonance behavior. Simple step tests are often used to estimate ID model parameters; namely, delay time and backwater surface area. These step tests change the canal inflow at the upstream end of the pool and observe water depth variations at the downstream end. Some knowledge of the canal pool characteristics are needed to determine the amount of flow change and its duration. Auto tune variation (ATV) is ...
Apr 1, 2011 in ICNSC (International Conference on Networking, Sensing and Control)
#1Guanghua Guan (WHU: Wuhan University)H-Index: 2
#2Changde Wang (WHU: Wuhan University)H-Index: 2
Last.Albert J. Clemmens (ARS: Agricultural Research Service)H-Index: 22
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One key problem for canal system control is how to select appropriate performance indicators and how to tune the controller with these indicators. A canal system is a multi-input and multi-output (MIMO) system. The judging control performance can be extremely complicated. In this paper, frequently used canal system performance indicators are evaluated. Then these indicators are used individually to tune the control parameters for a simple proportional-integral (PI) controller on a test canal. Th...
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