scholarly journals Application of Philip infiltration model to film hole irrigation

2018 ◽  
Vol 19 (3) ◽  
pp. 978-985 ◽  
Author(s):  
Yanwei Fan ◽  
Jiaguo Gong ◽  
Ying Wang ◽  
Xiaoxia Shao ◽  
Tong Zhao
Keyword(s):  
Influencing Factors ◽  
Power Function ◽  
Water Depth ◽  
Soil Texture ◽  
Hole Diameter ◽  
Model Parameters ◽  
Initial Water Content ◽  
Infiltration Model ◽  
Cumulative Infiltration ◽  
Function Relationship

Abstract Numerical simulations were carried out with HYDRUS-2D to investigate the influence of soil texture, initial water content, film hole diameter and water depth on cumulative infiltration from a film hole. Soil texture, film hole diameter and water depth are the dominant influencing factors. Philip infiltration model was used to fit the simulated results of the dominant influencing factors. For the same soil, the sorptivity (s) is a power function relationship with film hole diameter, while the steady infiltration rate (a) is a power function relationship with film hole diameter and water depth. On that basis, the calculation formulas for predicting s and a were established, and a simplified film hole infiltration model including the film hole diameter and water depth was proposed. The effectiveness of the model was verified by laboratory experiments and literature data. The predicted values of the model were in good agreement with the experimental observations. The model parameters can be determined only by a set of film hole infiltration experiment, which simplifies the experimental design and can be used as a tool for irrigation engineers or farmers to estimate cumulative infiltration.

scholarly journals Predicted Infiltration for Sodic/Saline Soils from Reclaimed Coastal Areas: Sensitivity to Model Parameters

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Dongdong Liu ◽  
Dongli She ◽  
Shuang’en Yu ◽  
Guangcheng Shao ◽  
Dan Chen
Keyword(s):  
Water Movement ◽  
Soil Surface ◽  
Coastal Areas ◽  
Model Parameters ◽  
Wetting Front ◽  
Sodic Soils ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Soil Physical Quality ◽  
Cumulative Infiltration

This study was conducted to assess the influences of soil surface conditions and initial soil water content on water movement in unsaturated sodic soils of reclaimed coastal areas. Data was collected from column experiments in which two soils from a Chinese coastal area reclaimed in 2007 (Soil A, saline) and 1960 (Soil B, nonsaline) were used, with bulk densities of 1.4 or 1.5 g/cm3. A 1D-infiltration model was created using a finite difference method and its sensitivity to hydraulic related parameters was tested. The model well simulated the measured data. The results revealed that soil compaction notably affected the water retention of both soils. Model simulations showed that increasing the ponded water depth had little effect on the infiltration process, since the increases in cumulative infiltration and wetting front advancement rate were small. However, the wetting front advancement rate increased and the cumulative infiltration decreased to a greater extent whenθ0was increased. Soil physical quality was described better by theSparameter than by the saturated hydraulic conductivity since the latter was also affected by the physical chemical effects on clay swelling occurring in the presence of different levels of electrolytes in the soil solutions of the two soils.

scholarly journals Triaxial Wetting Test on Rockfill Materials under Stress Combination Conditions of Spherical Stress p and Deviatoric Stress q

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Yan-yi Zhang ◽  
Ze-ping Xu ◽  
Gang Deng ◽  
Yan-feng Wen ◽  
Shu Yu ◽  
...  
Keyword(s):  
Shear Strain ◽  
Power Function ◽  
Volumetric Strain ◽  
Deviatoric Stress ◽  
Dry Density ◽  
Initial Water Content ◽  
Test Results ◽  
Rockfill Materials ◽  
Function Relationship ◽  
Wetting Deformation

A GCTS medium-sized triaxial apparatus is used to conduct a single-line method wetting test on three kinds of rockfill materials of different mother rocks such as mixture of sandstone and slate, and dolomite and granite, and the test stress conditions is the combination of spherical stress p and deviatoric stress q. The test results show that (1) for wetting shear strain, the effects of spherical stress p and deviatoric stress q are equivalent, and wetting shear strain and deviatoric stress q show the power function relationship preferably. (2) For wetting volumetric strain, the effect of deviatoric stress q can be neglected because it is extremely insignificant, and spherical stress p is the main influencing factor and shows the power function relationship preferably. (3) The wetting strains decrease significantly with the increase in initial water content and sample density generally, but the excessively high dry density will increase the wetting deformation. Also, the wetting strains will decrease with the increase in the saturated uniaxial compressive strength and average softening coefficient of the mother rock. Based on the test results, a wetting strain model is proposed for rockfill materials. The verification results indicate that the model satisfactorily reflects the development law of wetting deformation.

scholarly journals Research on Influence of Soil Moisture Content of Farmland on Infiltration Model Parameters

2020 ◽  
Vol 189 ◽  
pp. 01011
Author(s):  
Zhiwei Zheng ◽  
Zhuozhuo Gao
Keyword(s):  
Moisture Content ◽  
Soil Column ◽  
Initial Moisture Content ◽  
Test Method ◽  
Model Parameters ◽  
Initial Water Content ◽  
Initial Water ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Kostiakov Model

In order to study the influence of the initial moisture content on the parameters of the infiltration model using an indoor soil column test method, and the relationship between the initial moisture content and each model parameter was analyzed by using the Green-Ampt model, the Kostiakov model, and the Horton model. The results show that there is a certain relationship between the initial water content and the parameters of the infiltration model. Based on comprehensive considerations, the Kostiakov model is the best surface irrigation infiltration model, and the Kostiakov model has the best effect when the observation time is not less than 80 minutes to simulate the soil infiltration process.

scholarly journals Short-term power load forecasting based on support vector machine and particle swarm optimization

2018 ◽  
Vol 13 ◽  
pp. 174830181879706 ◽  
Author(s):  
Song Qiang ◽  
Yang Pu
Keyword(s):  
Support Vector Machine ◽  
Particle Swarm Optimization ◽  
Influencing Factors ◽  
Load Forecasting ◽  
Particle Swarm ◽  
Forecast Accuracy ◽  
Support Vector ◽  
Model Parameters ◽  
Short Term ◽  
Swarm Optimization

In this work, we summarized the characteristics and influencing factors of load forecasting based on its application status. The common methods of the short-term load forecasting were analyzed to derive their advantages and disadvantages. According to the historical load and meteorological data in a certain region of Taizhou, Zhejiang Province, a least squares support vector machine model was used to discuss the influencing factors of forecasting. The regularity of the load change was concluded to correct the “abnormal data” in the historical load data, thus normalizing the relevant factors in load forecasting. The two parameters are as follows Gauss kernel function and Eigen parameter C in LSSVM had a significant impact on the model, which was still solved by empirical methods. Therefore, the particle swarm optimization was used to optimize the model parameters. Taking the error of test set as the basis of judgment, the optimization of model parameters was achieved to improve forecast accuracy. The practical examples showed that the method in the work had good convergence, forecast accuracy, and training speed.

scholarly journals Numerical investigation of wetting front migration and soil water distribution under vertical line source irrigation with different influencing factors

2021 ◽  
Author(s):  
Yanwei Fan ◽  
Liangjun Ma ◽  
Hujun Wei ◽  
Pengcheng Zhu
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Influencing Factors ◽  
Line Source ◽  
Vertical Line ◽  
Initial Water Content ◽  
Wetting Front ◽  
Simulation Results ◽  
Soil Wetting

Abstract Vertical line source irrigation (VLSI) is an underground irrigation method suitable for deep-rooted plants. Understanding the characteristics of the soil wetting body of the VLSI was the key to designing this irrigation system. On the basis of experimental verification of the reliability of the HYDRUS simulation results of VLSI under the conditions of soil texture (ST), initial water content (θi), line source buried depth (B), line source diameter (D) and line source length (L), numerical studies of the migration law of the wetting front of VLSI and the distribution characteristics of soil moisture were performed. The wetting front migration (WFM) was mainly influenced by ST, θi, D and L (P < 0.05), while B had little effect on WFM (P > 0.05). The shape of the soil wetting body changed little under different influencing factors. The water content contour was approximately ‘ellipsoidal’ around the line source. The soil moisture near the line source was close to the saturated moisture content. The moisture content around the line source gradually decreased outward, and the contour lines gradually became dense. According to the simulation results, a prediction model of multiple factors influencing the migration process of the VLSI wetting front was established. The predicted value was in good agreement with the measured value. The results of this research could provide a theoretical basis for further optimizing the combination of VLSI and irrigation elements.

Numerical Simulation of Mixed Emulsion Explosive Charging in Water-Filled-Hole

2013 ◽  
Vol 634-638 ◽  
pp. 3563-3566
Author(s):  
Hai Wang Ye ◽  
Dong Ling Nong ◽  
Ting Li ◽  
Jie Wang Ye
Keyword(s):  
Numerical Simulation ◽  
Water Column ◽  
Water Depth ◽  
Jet Flow ◽  
Hole Diameter ◽  
Water Levels ◽  
Effective Range ◽  
Emulsion Explosive ◽  
Hole Bottom

When charging in water-filled-hole with emulsion mixed loading truck, if the charging hose can not reach the borehole bottom, there will be a water column in the charge. Emulsion explosive charging in water-filled-hole is simulated under three conditions with different water levels, charging velocity and hole diameter when the hose of the explosive mixed loading truck does not reach the hole bottom. The results show that explosive can not reach the bottom of the blasthole if the water depth exceeds the maximum effective range of the jet flow, which is proportional to charging speed and hole diameter, and there will exist a water column at the bottom of the hole. To prevent that, the distance between the hose outlet and the hole bottom must be shorter than the effective range when charging. Besides, increasing charging velocity also works.

scholarly journals An Empirical Model for Estimating Soil Thermal Diffusivity from Texture, Bulk Density, and Degree of Saturation

2018 ◽  
Vol 19 (2) ◽  
pp. 445-457 ◽  
Author(s):  
Xiaoting Xie ◽  
Yili Lu ◽  
Tusheng Ren ◽  
Robert Horton
Keyword(s):  
Thermal Diffusivity ◽  
Bulk Density ◽  
Empirical Model ◽  
Soil Texture ◽  
Degree Of Saturation ◽  
Model Parameters ◽  
Near Surface ◽  
New Model ◽  
Soil Thermal Diffusivity ◽  
Mean Square Errors

Abstract Soil thermal diffusivity κ is an essential parameter for studying surface and subsurface heat transfer and temperature changes. It is well understood that κ mainly varies with soil texture, water content θ, and bulk density ρb, but few models are available to accurately quantify the relationship. In this study, an empirical model is developed for estimating κ from soil particle size distribution, ρb, and degree of water saturation Sr. The model parameters are determined by fitting the proposed equations to heat-pulse κ data for eight soils covering wide ranges of texture, ρb, and Sr. Independent evaluations with published κ data show that the new model describes the κ(Sr) relationship accurately, with root-mean-square errors less than 0.75 × 10−7 m2 s−1. The proposed κ(Sr) model also describes the responses of κ to ρb changes accurately in both laboratory and field conditions. The new model is also used successfully for predicting near-surface soil temperature dynamics using the harmonic method. The results suggest that this model provides useful estimates of κ from Sr, ρb, and soil texture.

Experimental study on the wave height distribution of wind-induced waves in the growth stage under finite water depth

2019 ◽  
Vol 19 (8) ◽  
pp. 2270-2279
Author(s):  
Ang Gao ◽  
Shiqiang Wu ◽  
Li Chen ◽  
Sien Liu ◽  
Zhun Xu ◽  
...  
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Growth Stage ◽  
Wind Wave ◽  
Model Parameters ◽  
Height Distribution ◽  
Distribution Models ◽  
Wave Height Distribution ◽  
Comparison Results ◽  
Optimized Model

Abstract With the method of a wind tank experiment, the real scenario of lakes with horizontal and vertical circulation of wind-induced flows is considered, and the features of wind wave height and its distribution in the different conditions of wind blowing distance, wind speed and water depth are studied systematically. Afterwards, comparison of the wave height distributions derived directly from experiment and the typical wave height distribution models show that some defects exist in typical wave height distribution models when describing wind wave height distribution in the wave growth stage. On this basis, we propose a new distribution model which is suitable for the description of wind wave height during the growth stage, and the model parameters are acquired with the programming solution method. Finally, the model is further optimized by relating B to σa, and Hs to σa. Comparison results of the optimized model and the typical ones show that the optimized model has advantages in calculation accuracy and convenience of use.

A Forecasting Method of Kostiakov Infiltration Model Parameters Based on Back-Propagation Model

2012 ◽  
Vol 610-613 ◽  
pp. 2899-2903
Author(s):  
Chong Wen Cao ◽  
Gui Sheng Fan
Keyword(s):  
Back Propagation ◽  
Influence Factors ◽  
Propagation Model ◽  
Water Infiltration ◽  
Physical Parameters ◽  
Model Parameters ◽  
Soil Infiltration ◽  
Infiltration Process ◽  
Infiltration Model ◽  
Bp Model

Based on test data of field soil water infiltration, Back-propagation (BP) model of predicting Kostiakov infiltration model parameters was established after analyzing the primary influence factors of water infiltration model parameters. The results indicate that BP model can reflect the non-linear relationship between the model parameters and the physical parameters of the soil; BP model is high accuracy for prediction soil infiltration model parameters. It can be referred as a new method to predict soil infiltration process using soil physical parameters.

scholarly journals Effect of soil texture on water infiltration in semiarid reclaimed land

2015 ◽  
Vol 51 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Wenmei Ma ◽  
Xingchang Zhang ◽  
Qing Zhen ◽  
Yanjiang Zhang
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Properties ◽  
Soil Texture ◽  
Soil Depth ◽  
Water Infiltration ◽  
Empirical Coefficient ◽  
Reclaimed Land ◽  
Essential Information ◽  
Disturbed Land ◽  
Cumulative Infiltration

The infiltration of water and its influencing factors in disturbed or reclaimed land are not well understood. A better understanding would provide essential information for assessing the hydrological processes in disturbed ecosystems. We measured the infiltration of water in soils from loamy and sandy reclaimed land. The relationships between infiltration and soil properties were analyzed based on three models: the Kostiakov, Philip, and Green–Ampt equations. Our objectives were to understand water infiltration in reclaimed land with a variety of soil textures and to establish the dependence of water infiltration on soil properties. Both the rate of infiltration and the cumulative infiltration were higher in sandy than in loamy soils. The rate of infiltration and the cumulative infiltration decreased with soil depth in undisturbed land. The sorptivity rate (S) from the Philip equation, empirical coefficient (K) from the Kostiakov equation, and the satiated hydraulic conductivity (Ksl) from the Green–Ampt equation were 22%, 16%, and 7.1% higher, respectively, in sandy than in loamy soils. The Ksl increased significantly with Ks (saturated hydraulic conductivity) in both sandy and loamy soils. These indicated that the Green–Ampt equation can be used to describe Ks and the characteristics of infiltration for soils on disturbed land.

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