Department of Civil Engineering

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Author: search.filters.author.Munusamy, Selva BalajiSubject: search.filters.subject.Civil Engineering

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Now showing 1 - 5 of 5
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    Can We Remove Secular Terms for Analytical Solution of Groundwater Response under Tidal Influence?
    (ARXIV, 2016-05) Munusamy, Selva Balaji
    This paper presents a secular term removal methodology based on the homotopy perturbation method for analytical solutions of nonlinear problems with periodic boundary condition. The analytical solution for groundwater response to tidal fluctuation in a coastal unconfined aquifer system with the vertical beach is provided as an example. The non-linear one-dimensional Boussinesq's equation is considered as the governing equation for the groundwater flow. An analytical solution is provided for non-dimensional Boussinesq's equation with cosine harmonic boundary condition representing tidal boundary condition. The analytical solution is obtained by using homotopy perturbation method with a virtual embedding parameter. The present approach does not require pre-specified perturbation parameter and also facilitates secular terms elimination in the perturbation solution. The solutions starting from zeroth-order up to third-order are obtained. The non-dimensional expression, A/D∞ emerges as an implicit parameter from the homotopy perturbation solution. The non-dimensional solution is valid for all ranges of A/D values. Higher order solution reveals the characteristics of the tidal groundwater table fluctuations.
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    Optimal Control of Saltwater Intrusion in Coastal Aquifers Using Analytical Approximation Based on Density Dependent Flow Correction
    (Springer, 2020-01) Munusamy, Selva Balaji
    Pumping well management in coastal aquifers required to account for the saltwater intrusion problem. The prevention saltwater contamination of pumping wells should be considered along with the objective of maximum groundwater withdrawal. Saltwater intrusion constraint can be based on (1) sharp interface model (2) density-dependent transport model. Sharp interface models are preferable in the case of limited computation cost available and density-dependent transport models are preferable for accuracy. The correction factor introduced to account for the density-dependent dispersion by Pool and Carrera (Water Resour Res 47(5):W05506, 2011) vastly improves the sharp interface solution. In this present study, the application of the modified sharp interface solution based on the density-dependent correction factor for the pumping optimization is demonstrated for a regional scale aquifer in Nellore, Andhra Pradesh, India. The proposed optimization model sought to maximize the total pumping and minimize the landward toe intrusion from the sea.
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    Experimental and numerical investigation of saltwater intrusion dynamics on sloping sandy beach under static seaside boundary condition
    (Elsevier, 2020-10) Munusamy, Selva Balaji
    Two-dimensional sandbox experiments were conducted to investigate the variable-density circulation and flow patterns in sloping beach configurations. The experiments provide new benchmark results for validating the sandbox models based on quantitative and qualitative measurements. Previous studies have considered density dependent flow in porous media, vertical beach face saltwater boundary, and multilayered hydrogeology ignoring a sloping beach face, which is a much more common phenomenon in real world. The present study considers sloping beach face under both homogeneous and low-permeability strata configurations. The geohydraulic processes encountered were quantified through pore-water pressure measurements and image analysis techniques. Moreover, validations were performed with numerical simulations (FEFLOW). A simple image analysis procedure is proposed with respect to two-dimensional laboratory scale benchmark experiments. Experimental results provided a detailed circulation flow path within and outside the saltwater wedge with sloping beach face. Fingering effect in porous media was also observed for both the experiments during initial time periods. Stability analysis shows the existence of a stationary convective flow pattern followed by gravitational instabilities under the quasi-steady state condition.
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    Appraising the Accuracy of Multi-Class Frequency Ratio and Weights of Evidence Method for Delineation of Regional Groundwater Potential Zones in Canal Command System
    (Springer, 2017-06) Munusamy, Selva Balaji
    A comparative study of probabilistic frequency ratio (FR) and weights of evidence (WofE) method is performed for delineation of regional groundwater potential zones (GPZ) in canal command system. In the present case study, delineation of GPZ in the Hirakud agricultural command area of Odisha, India. Field discharge data from borewells are utilized for the analysis along with remote sensing (RS) and geographic information system (GIS) techniques. Various influencing attributes responsible for occurrence and movement of groundwater, e.g., land use / land cover, soil type, groundwater depth, geology, elevation, geomorphology, slope, recharge rate, rainfall, normalized difference vegetation index, drainage density, crop intensity are integrated by using GIS platform. Model results from FR and WofE show similar trends. The middle portion of the study area covers the ‘Good’ GPZ. Sensitivity analyses are performed for FR and WofE methods.
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    Delineation of Groundwater Potential Zones of Coastal Groundwater Basin Using Multi-Criteria Decision Making Technique
    (Springer, 2016-07) Munusamy, Selva Balaji
    Delineation of groundwater potential zones (GWPZ) has been performed for a coastal groundwater basin of eastern India. The groundwater potential zone index (GWPZI) map is generated by using Analytic Hierarchy Process (AHP) from different influencing features, e.g., Land Use/Land Cover (LU/LC), soil (S), geomorphology (GM), hydrogeology (HG), surface geology (SG), recharge rate (RR), drainage density (DD), rainfall (RF), slope (Sl), surface water bodies (SW), lineament density (LD), and Normalized Difference Vegetative Index (NDVI). Recharge rate values are estimated from hydrological water balance model. Overlay weighted sum method is used to integrate all thematic feature maps to generate GWPZ map of the study area. Four zones have been identified for the coastal groundwater basin [very good: 36.39 % (273.53 km2, good: 43.57 % (327.47 km2), moderate: 18.27 % (137.30 km2), and poor: 1.77 % (13.27 km2)]. Areas in north to south-west and south-east direction show very good GWPZ due to the presence of low drainage density. GWPZ map and well yield values show good agreement. Sensitivity analysis reveals that exclusion/absence of rainfall and lineament density increases the poor groundwater potential zones. Omission of hydrogeology, soils, surface geology, and NDVI show maximum increase in good GWPZ. Obtained GWPZ map can be utilized effectively for planning of sustainable agriculture. This analysis demonstrates the potential applicability of the methodology for a general coastal groundwater basin.