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S. Murty Bhallamudi

Bio: S. Murty Bhallamudi is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Flow (mathematics) & Biodegradation. The author has an hindex of 28, co-authored 75 publications receiving 1930 citations. Previous affiliations of S. Murty Bhallamudi include Indian Institute of Technology Kanpur & Indian Institutes of Technology.


Papers
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TL;DR: In this article, a mathematical model is presented to predict bed-level changes due to sediment overloading, development of longitudinal profile due to base-level lowering, and bed level changes associated with the migration of knickpoints.
Abstract: The Saint-Venant equations describing unsteady flow in open channels and the continuity equation for the conservation of sediment mass are numerically solved to determine the aggradation and degradation of channel bottom due to an imbalance between water flow and sediment discharge. For this purpose, the MacCormack explicit finite-difference scheme is introduced. This scheme is second-order accurate, handles shocks and discontinuities in the solution without any special treatment, and allows simultaneous solution of the water and sediment equations, thereby obviating the need for iterations. The sediment transport relationship in any form may be included in the computations. Computational procedures are outlined for incorporating the typical boundaries for hydraulic engineering applications. The mathematical model presented here is applied to predict (1) Bed-level changes due to sediment overloading; (2) development of longitudinal profile due to base-level lowering; (3) and bed-level changes associated with the migration of knickpoints. The computed results are compared with the available experimental data obtained on laboratory flumes. The agreement between the computed and experimental results is satisfactory.

105 citations

Journal ArticleDOI
TL;DR: A transfer function model of a gas pipeline is used as a basis for developing a dynamic simulator for gas pipeline networks and the ability of the proposed approach for obtaining accurate state estimation from noisy measurements is demonstrated through simulations on an example network.
Abstract: Dynamic simulation models of gas pipeline networks can be used for on-line applications such as state estimation, leak detection, etc. A prime requirement for such models is computational efficiency. In this paper, a transfer function model of a gas pipeline is used as a basis for developing a dynamic simulator for gas pipeline networks. The simulator is incorporated in a data reconciliation framework, which is ideally suited for on-line state estimation based on all available measurements of pressures and flow rates. The American Gas Association (AGA) model is used for making realistic computations of the gas compressibility. Accuracy and computational efficiency of the proposed method are evaluated by comparing our results with those obtained using a fully nonlinear second-order accurate finite difference method. The ability of the proposed approach for obtaining accurate state estimation from noisy measurements is demonstrated through simulations on an example network. We also demonstrate the use of the proposed approach for estimating an unknown demand at any node by exploiting the redundancy in measurements.

97 citations

Journal ArticleDOI
TL;DR: In this article, a multiobjective optimization framework for optimal waste load allocation in rivers is proposed, considering the total treatment cost, the equity among the waste dischargers, and a comprehensive performance measure that reflects the dissolved oxygen (DO) violation characteristics.
Abstract: A multiobjective optimization framework for optimal waste load allocation in rivers is proposed, considering (1) the total treatment cost, (2) the equity among the waste dischargers, and (3) a comprehensive performance measure that reflects the dissolved oxygen (DO) violation characteristics. This framework consists of an embedded river water quality simulator that has a gradually varied flow module and a pollutant transport module, which simulates the transport process including reaction kinetics (in terms of biochemical oxygen demand-DO). The outer shell of the framework consists of the two nonseasonal, deterministic, multiobjective waste load allocation planning models, namely, cost-performance model and cost-equity-performance model. These models are solved using a powerful and recently developed multiobjective genetic algorithm technique known as the Nondominated Sorting Genetic Algorithm-II. The practical utility of the multiobjective framework in decision-making is illustrated through a realistic example of the Willamette River in the state of Oregon.

94 citations

Journal ArticleDOI
TL;DR: In this paper, a nonlinear programming approach using the successive quadratic programming optimization technique is developed for the optimal design of a pipeline network for water supply systems, which eliminates the equality constraints describing the hydraulics by a suitable choice of dependent and independent variables.
Abstract: In this study, a nonlinear programming approach using the successive quadratic programming optimization technique is developed for the optimal design of a pipeline network for water supply systems. The proposed method eliminates the equality constraints describing the hydraulics by a suitable choice of dependent and independent variables. The dependent variables are chosen based on graph theoretic decomposition of the network structure. This makes it possible to compute analytically the reduced constraints, objective function gradients, and reduced Hessian in a very efficient manner. This method of decomposition ensures that the nodal and loop balances are exactly satisfied and is robust for any initial starting point, able to handle incorrect initial flow directions. The method gives solutions comparable to the previous optimal solutions for the design of new as well as expansion of existing water distribution networks.

91 citations

Journal ArticleDOI
TL;DR: Impacts of land use changes on the water balance components are assessed for the near future employing four different climate conditions (baseline, IPCC A1B, dry, wet, wet) using SLEUTH projections as a dynamic input to the hydrologic model SWAT.

91 citations


Cited by
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Journal ArticleDOI
TL;DR: This review describes the environmental implications of Cr(VI) presence in aqueous solutions, the chemical species that could be present and then the technologies available to efficiently reduce hexavalent chromium.

1,063 citations

Journal ArticleDOI
TL;DR: A review of the state of the art in sea intrusion research can be found in this article, where the authors subdivide SI research into three categories: process, mea- surement, prediction and management.

1,055 citations

01 Jan 2004
TL;DR: In this paper, the effects of subinhibitory concentrations of antibiotics and disinfectants on environmental bacteria, especially with respect to resistance, are investigated and the impact on the frequency of resistance transfer by antibacterials present in the environment is questionable.
Abstract: Antibiotics, disinfectants and bacteria resistant to them have been detected in environmental compartments such as waste water, surface water, ground water, sediments and soils. Antibiotics are released into the environment after their use in medicine, veterinary medicine and their employment as growth promoters in animal husbandry, fish farming and other fields. There is increasing concern about the growing resistance of pathogenic bacteria in the environment, and their ecotoxic effects. Increasingly, antibiotic resistance is seen as an ecological problem. This includes both the ecology of resistance genes and that of the resistant bacteria themselves. Little is known about the effects of subinhibitory concentrations of antibiotics and disinfectants on environmental bacteria, especially with respect to resistance. According to the present state of our knowledge, the impact on the frequency of resistance transfer by antibacterials present in the environment is questionable. The input of resistant bacteria into the environment seems to be an important source of resistance in the environment. The possible impact of resistant bacteria on the environment is not yet known. Further research into these issues is warranted.

867 citations

Journal ArticleDOI
TL;DR: Thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes for a better understanding of each category.

758 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an overview of both historic developments and present research and practice in the field of hydraulic transients, including mass and momentum equations for one-dimensional flows.
Abstract: Hydraulic transients in closed conduits have been a subject of both theoretical stud intense practical interest for more than one hundred years. While straightforward in te of the one-dimensional nature of pipe networks, the full description of transient fluid fl pose interesting problems in fluid dynamics. For example, the response of the turbu structure and strength to transient waves in pipes and the loss of flow axisymme pipes due to hydrodynamic instabilities are currently not understood. Yet, such u standing is important for modeling energy dissipation and water quality in transient flows. This paper presents an overview of both historic developments and presen research and practice in the field of hydraulic transients. In particular, the paper cusses mass and momentum equations for one-dimensional Flows, wavespeed, nu solutions for one-dimensional problems, wall shear stress models; two-dimensional and momentum equations, turbulence models, numerical solutions for two-dimen problems, boundary conditions, transient analysis software, and future practical an search needs in water hammer. The presentation emphasizes the assumptions and tions involved in various governing equations so as to illuminate the range of applic ity as well as the limitations of these equations. Understanding the limitations of cu models is essential for (i) interpreting their results, (ii) judging the reliability of the da obtained from them, (iii) minimizing misuse of water-hammer models in both research practice, and (iv) delineating the contribution of physical processes from the contribu of numerical artifacts to the results of waterhammer models. There are 134 refrences in this review article.@DOI: 10.1115/1.1828050 #

630 citations