An approximate solution for two-dimensional groundwater infiltration in sewer systems

2013 ◽  
Vol 67 (2) ◽  
pp. 347-352 ◽  
Author(s):  
Shuai Guo ◽  
Tuqiao Zhang ◽  
Yiping Zhang ◽  
David Z. Zhu

Estimating groundwater infiltration into sewer systems is important for wastewater treatment operators and municipalities. This paper presents an approximate solution for steady-state groundwater infiltration into sewer systems through line defects. The groundwater table was assumed to be horizontal and the aquifer homogeneous and isotropic. Mobius transformation technique and equivalent circumference method were introduced to solve the governing equation. The infiltration rate is found to be controlled by the hydraulic conductivity of the surrounding soil, the total hydraulic head above the sewer pipe, the size of the sewer pipe, the position of the defect, and the size of the defect.

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Hassan Eltayeb ◽  
Imed Bachar ◽  
Yahya T. Abdalla

Abstract In this study, the double Laplace Adomian decomposition method and the triple Laplace Adomian decomposition method are employed to solve one- and two-dimensional time-fractional Navier–Stokes problems, respectively. In order to examine the applicability of these methods some examples are provided. The presented results confirm that the proposed methods are very effective in the search of exact and approximate solutions for the problems. Numerical simulation is used to sketch the exact and approximate solution.


2020 ◽  
Vol 21 (2) ◽  
pp. 139
Author(s):  
Evarista Ristin Pujiindiyati ◽  
Bungkus Pratikno

Aquifer in river bank area is mostly susceptive toward pollution occurring in river. One of parameters to determine the interaction process between groundwater and river is a natural isotope of 222Rn. The significant difference of radon concentration in groundwater and river water can be utilized as a scientific basis for investigating groundwater infiltration in river bank. Those studied parameters are residence time and infiltration rate. The research using 222Rn had been conducted in shallow groundwater of Ciliwung river bank - South Jakarta during rainy and dry season. The range of 222Rn concentration in shallow groundwater monitored in dry season was between 666 - 2590 Bq/m3 which was higher than that of rainy season ranging at 440 to 1546 Bq/m3. Otherwise, concentration of 222Rn in river water could not be detected (its 222Rn concentration = 0 Bq/m3) due to its much lower concentration either rainy or dry season. During dry season monitoring, equilibration between groundwater and river water was reached at the distance approximately 98 - 140 m away from river side. Estimating residence time based on 222Rn concentration at nearest site from the river and at equlibration area was 4.2 days such that the infiltration rate from river water into aquifer might be 7.8 m/day.Keywords: 222Rn, groundwater, residence time, infiltration rate.


2021 ◽  
Vol 878 (1) ◽  
pp. 012056
Author(s):  
M Situmorang ◽  
S Setiyadi ◽  
L E Hutabarat

Abstract Rainfall is a determining factor in analyzing planned floods. This research was conducted by collecting secondary data and the field data concerning the soil’s ability to infiltrate the volume of rainfall. Data processing is carried out by statistical analysis to estimate the average rainfall, intensity value, estimated discharge plan, volume of runoff and estimated infiltration rate. These parameters are important related to the infiltration well dimensions planning and the conserving water area. From the research results, it is shown that infiltration rate and optimal dimensions of infiltration wells very dependent on rainfall discharge and runoff volume in each region. Artificial infiltration is an alternative solution for maintaining groundwater balance and overcoming water problems. With groundwater infiltration, groundwater infiltration can maintain a relatively stable groundwater depth. Infiltration rate in RT 06 Cawang are 54,03 cm/hour lower than in Kelurahan 11 Cawang East Jakarta are 54,12 cm/hour, with perimeter area of wells DSP = 1,5 m2, Depth of well (HSP) = -1,89 m2 and coverage area of well (ASP) = 1,77 m2.


2020 ◽  
Vol 25 (5) ◽  
pp. 1101-1123 ◽  
Author(s):  
Lidong Fang ◽  
Apala Majumdar ◽  
Lei Zhang

We study nematic equilibria on rectangular domains, in a reduced two-dimensional Landau–de Gennes framework. These reduced equilibria carry over to the three-dimensional framework at a special temperature. There is one essential model variable, [Formula: see text], which is a geometry-dependent and material-dependent variable. We compute the limiting profiles exactly in two distinguished limits: the [Formula: see text] 0 limit relevant for macroscopic domains and the [Formula: see text] limit relevant for nanoscale domains. The limiting profile has line defects near the shorter edges in the [Formula: see text] limit, whereas we observe fractional point defects in the [Formula: see text] 0 limit. The analytical studies are complemented by some bifurcation diagrams for these reduced equilibria as a function of [Formula: see text] and the rectangular aspect ratio. We also introduce the concept of ‘non-trivial’ topologies and study the relaxation of non-trivial topologies to trivial topologies mediated via point and line defects, with potential consequences for non-equilibrium phenomena and switching dynamics.


Author(s):  
Abir Chaouk ◽  
Maher Jneid

In this study we use the conformable fractional reduced differential transform (CFRDTM) method to compute solutions for systems of nonlinear conformable fractional PDEs. The proposed method yields a numerical approximate solution in the form of an infinite series that converges to a closed form solution, which is in many cases the exact solution. We inspect its efficiency in solving systems of CFPDEs by working on four different nonlinear systems. The results show that CFRDTM gave similar solutions to exact solutions, confirming its proficiency as a competent technique for solving CFPDEs systems. It required very little computational work and hence consumed much less time compared to other numerical methods.


2020 ◽  
Vol 102 (7) ◽  
Author(s):  
Topi Kähärä ◽  
Pekka Koskinen

2009 ◽  
Vol 60 (3) ◽  
pp. 727-735 ◽  
Author(s):  
V. Prigiobbe ◽  
M. Giulianelli

The infiltration of parasitical water into two sewer systems in Rome (Italy) was quantified during a dry weather period. Infiltration was estimated using the hydrograph separation method with two water components and δ18O as a conservative tracer. The two water components were groundwater, the possible source of parasitical water within the sewer, and drinking water discharged into the sewer system. This method was applied at an urban catchment scale in order to test the effective water-tightness of two different sewer networks. The sampling strategy was based on an uncertainty analysis and the errors have been propagated using Monte Carlo random sampling. Our field applications showed that the method can be applied easily and quickly, but the error in the estimated infiltration rate can be up to 20%. The estimated infiltration into the recent sewer in Torraccia is 14% and can be considered negligible given the precision of the method, while the old sewer in Infernetto has an estimated infiltration of 50%.


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