Venkat Kolluru

University of Rhode Island | URI · Department of Ocean Engineering

A mechanistic model was developed to assist with design of constructed wetlands intended to treat industrial wastewater in the Arabian Gulf region. The model is deterministic in nature and thus allows explicit evaluation of the fate and transport of wastewater constituents throughout constructed wetlands to assess their efficacy in treatment. Altho...

The hydrodynamic and transport characteristics of the Baltic Sea in the period 2000–2009 were studied using a fully calibrated and validated 3D hydrodynamic model with a horizontal resolution of 4.8 km. This study provided new insight into the type and dynamics of vertical structure in the Baltic Sea, not considered in previous studies. Thermal and...

The Pacific oyster, Crassostrea gigas, is an invasive species with a large increase in prevalence globally, and with potential of spreading even more because of climate-change effects. We examined how future climate might affect its potential for spread at its northern distribution limit in a temperate ecoregion, by simulating spawning, larval disp...

Chlorine is used commonly to prevent biofouling in cooling water systems. The addition of chlorine poses environmental risks in natural systems due to its tendency to form chlorination by-products (CBPs) when exposed to naturally-occurring organic matter (NOM). Some of these CBPs can pose toxic risks to aquatic and benthic species in the receiving...

Ballast water systems in large LNG carriers are essential for proper operations and stability. Water withdrawn from the surrounding environment to supply to the ballast can pose entrainment and impingement risk to the resident fish population. Quantification of these risks and the net effect on population is usually quite challenging and complex. V...

Use of complex mathematical models and geospatial information systems (GIS) has traditionally been a mutually exclusive process. Spatial and temporal modeling is performed using a suite of well-established numerical models for a particular domain or area of interest (AOI) and outputs are produced for the same domain framework. GIS, on the other han...

A 3-dimensional hydrodynamic model was developed to simulate thermal mixing zones and predict the fate of residual chlorine and chlorination by-products (CBPs) from industrial cooling water discharged to a shallow coastal environment influenced by strong tides and winds (the Arabian Gulf). This model is novel since the individual and cumulative eff...

A 3-dimensional hydrodynamic model was developed and calibrated to simulate the thermal mixing zone and predict the fate of residual chlorine and chlorination by-products (CBP) from industrial cooling water discharged from Ras Laffan City. This model is novel since the individual and cumulative effects of cooling water discharges from several outfa...

A numerical three-dimensional hydrodynamic and transport model was developed to study the fate of chlorination by-products in the coastal waters near an industrial city in northeastern Qatar. Field data collected on two separate occasions during the second half of 2006 were used to calibrate and validate the model. Good agreement between model resu...

A recent model application has been developed by the Washington State Dept. of Ecology that simulates water circulation in South Puget Sound (SPS) using the Generalized Environmental Modeling System for Surface waters (GEMSS) with an open northern boundary near Edmonds, WA. Post-calibration root mean square errors (RMSEs) are <5% of Ehe tidal range...

Water quality monitoring and assessment studies suggest high concentrations of nitrogen and phosphorus within the Delaware Inland Bays located in Sussex County in southern Delaware. These nutrients are essential for both plants and animals of the Inland Bays. However, in large quantities they may negatively impact the ecology of the bays. Some symp...

A combined 3-D and 1-D modeling system was developed to include many streams, ponds and lakes that enter multiple receiving water bodies. The combined model will be used as a management tool for TMDL (Total Maximum Daily Load) studies in the Delaware's Inland Bays. The Inland Bays TMDL study region consist of 19 river networks with two to ten tribu...

The influence of multi algal groups in the calibration of a water quality model was discussed. The proposed model includes the release of spores/cyst vegetative cells from the sediment at a designated time, their transport through the water column column, and their transformation to algae. The results show that at the surface there is a very small...

The objective of this study is to examine the influence different zooplankon grazing rate relationships have on water quality eutrophication model results in a tidal estuary. The water quality model being used includes phytoplankton and both dissolved and particulate constituents as state variables. It includes zooplankton grazing of the phytoplank...

The evaluation of the mixing zone for a proposed expansion to a liquefied natural gas facility on the northeast coast of the State of Qatar in support of an environmental impact assessment was performed using the Generalized Environmental Modeling System for Surface Waters (GEMSS). The circulating seawater at the facility absorbs heat during the li...

To assess potential aquatic injury from oil spills, a fate and transport model called the Chemical / Oil Spill Impact Module (COSIM) was developed based upon refinements made to the NOAA Natural Resource Damage Assessment Model (NRDAM). Enhanced mass balance of the oil enabled better tracking of specific oil components of toxicological concern. The...

The evaluation of the mixing zone as part of the EIA for a proposed two-train (55,000 m3/hr) and four-train (135,000 m3/hr) flow rates of seawater at the RasGas liquefied natural gas (LNG) facility on the northeast coast of the State of Qatar was done through the use of Generalized Environmental Modeling System for Surface waters called GEMSS. The...

Accurate simulation of the temperature distribution in a cooling lake or reservoir is often required for feasibility studies of engineering options that increase the cooling capacity of the waterbody. A three-dimensional hydrodynamic and temperature model has been developed and applied to several cooling lakes in the south-eastern United States. In...

Power plant condenser cooling water intake entrainment of fish eggs and larvae is becoming an issue in evaluating environmental impacts around the plants. Methods are required to evaluate intake entrainment on different types of water bodies. Presented in this paper is a derivation of the basic relationships for evaluating entrainment from the stan...

The setting up of the grid in any three dimensional hydrodynamic and transport model takes a considerable amount of time even with the use of grid generation software. The effort increases with the complexity of the water body. Refining the grid for proposed design elements such as jetties, breakwaters, and curtain walls becomes especially time con...

The acceleration and dispersion terms in the vertical direction are developed for the 3-D hydrodynamic and transport model GLLVHT. With these additional terms, the model was extended to simulate the effects of a compressed air bubbler on the vertical temperature structure of a reservoir used as a source of cooling water for a thermal power plant. T...

The distribution of constituents from discharges in estuaries can be determined only to the detail with which the time-varying velocity field is known. Deep estuaries can exhibit complex vertical and horizontal circulation structures depending on tides, freshwater inflows, density stratification, and geometry. A numerical, time-varying, three-dimen...

A state-of-the-art, three-dimensional oil spill model (WOSM/OILMAP) was applied to hindcast the transport and fate of the Braer oil spill, which occurred off the southern coast of Shetland Island in January 1993. The model included advection, spreading, evaporation, emulsification, entrainment, oil-shoreline interaction, and subsurface transport. T...

The spectral and hydrodynamic response of laminar flow over a flat plate with a vibrating section forced in sinusoidal motion with a dimensionless amplitude ratio, H[sub 0] (vibration amplitude divided by plate length) varying in the range 0.0 < H[sub 0] < 0.1 is analyzed using numerical simulations. The Reynolds number, Re, based on the length of...

A computer model developed by Venkat and Spaulding (1991) for unsteady flows over vibrating bodies is used to investigate the nonlinear characteristics of external flow over a flat plate, a section of which is subjected to time varying motion of various mode shapes (n). Simulations are performed for modes varying in the range 1-4. For n = 1, upstre...

A model is developed to simulate two-dimensional laminar flow over an arbitrarily shaped body, a portion of which is subjected to time varying harmonic motion. The model is tested by comparison to previous numerical simulations for flow over a square cavity, oscillatory flow through a wavy channel and boundary layer flow along a flat plate. The mod...

A model is developed to simulate two-dimensional laminar flow over an arbitrarily shaped body, a part of which is subjected to simple harmonic motion. The vibration amplitude ratio, H0, and the Reynolds number, Re, are maintained at 0.1 and 1000, respectively. The Strouhal number, St, is varied in the range 0.0 ≤ St ≤ 1.0. The computer code is test...

Engineering applications of unsteady boundary layers are numerous and of great importance in hydro and aero dynamics. Relatively little research however is focussed on understanding the flow structure if the perturbations in the flow are caused by the motion of flexible boundaries rather than by time dependent variations in the flow itself. A model...

A two-dimensional potential-flow model is employed to predict the wave and flow fields generated by wedge, circular, and semicircular cylinders and ship-shaped bodies in forced heaving motion. The case of a wedge penetrating still fluid at constant velocity is also studied. The model solves the potential flow equation, including the full nonlinear...

The purpose of the study is to show the application of combined hydrodynamic and water quality modeling, and to examine the predication of phytoplankton densities in a tidal situation using a traditional first order zooplankton grazing rate formulation versus using a density dependent grazing rate formulation. THE HYDRODYNAMIC MODEL The hydrodynami...

Paper presented at The Seventh International Conference on HydroScience and Engineering (ICHE) hosted by the College of Engineering at Drexel Univeristy on September 10-13, 2006 in Philadelphia, Pennsylvania. The conference theme was IT in the Field of HydroSciences. It included several mini-symposia that emphasized IT topics in HydroSciences and t...