Faculty Publications

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    Study of dynamic changes through geoinformatics technique: A case study of Karwar coast, west coast of India
    (Springer, 2019) Yadav, A.; Dodamani, B.M.; Dwarakish, G.S.
    Shoreline is one of the geo-indicators of the coastal zone. Coastal zone is subjected to threats due to change in shoreline. Shoreline change leads to modification and causes for damages of properties, infrastructure around the shoreline region. These modifications, changes of land expands too many issues of the environment under the coastal zone. The present study was carried out by employing remote sensing and GIS techniques for the coastal regime of Karwar, India. LANDSAT-8 remote sensing data was integrated with the GPS data collected during the field survey. The satellite data is processed and analyzed using ERDAS IMAGINE 2014 tool and ArcGIS 10.3 tool, respectively. High Water Line (HWL) is considered for the extraction of shoreline. The visual interpretation of satellite imageries is carried out to distinguish the HWL. Net Shoreline Movement (NSM) was evaluated by adopting Digital Shoreline Analysis System (DSAS) tool. Statistical methods such as Weighted Linear Regression (WLR), Linear Regression Rate (LRR) and End Point Rate (EPR) were used to estimate the changes of shoreline. The present study reveals that shorelines of Karwar Coast, Ravindranath Taghore beach experiences an average erosion rate is −4.61 m/year (EPR), −1.49 m/year (LRR), and 0.19 (WLR) and Devbagh beach experiences an average erosion rate is −9.74 m/year (EPR), −7.53 m/year (LRR), and −11.55 m/year (WLR). © Springer Nature Singapore Pte Ltd. 2019.
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    Impacts of dams on sediment yield and coastal processes using swat and dsas tools
    (Springer Science and Business Media Deutschland GmbH, 2021) Athira, K.; Yadav, A.; Dodamani, B.M.; Dwarakish, G.S.
    Soil erosion is considered as one of the major causes of land degradation and reservoir sedimentation. Therefore, modeling of runoff and sediment yield at the catchment level is necessary. In this study, an attempt was made to simulate runoff and sediment yield of hydrologically similar basins of Kali River and Aghanashini River which joins west coast of India. A conceptual, continuous time and semi-distributed SWAT2012 (Soil and Water Assessment Tool) model was selected for the modeling purpose. For the last two decades, Kali river basin experienced a very high rate of soil erosion due to various developmental activities in the basin. Therefore, it is essential to identify the soil loss within the basin. There are five dams constructed across the Kali river basin for various purposes. The presence of these reservoirs regulates stream flow and thus sediment load in the basin. However, the free movement of water across the Aghanashini river catchment leads to the unobstructed passage of sediments to the river mouth, as the catchment is not disturbed by the reservoir. This study deals with the impacts of the dams on stream flow, sediment load and the response of shoreline. Digital Shoreline Analysis System (DSAS) tool was used to analyze the shoreline changes. Simulated and observed values of runoff are compared, and calibration and validation were done for the basins using SWAT-CUP. Analysis of calibration and validation results shows that the model has a good performance. Therefore, the SWAT model can be used to conduct further studies in these study areas. Sediment yield obtained at the catchment outlet was 1.07 t/ha/year and 4.58 t/ha/year for Kali and Aghanashini basins, respectively. Less amount of sediment load in the Kali basin indicate the influence of reservoir operation on stream flow and sediment yield. The shoreline analysis of both the basins concluded that Devbagh beach connecting with Kali river estuary is under erosion and Aghanashini beach is under naturally nourished condition. © Springer Nature Singapore Pte Ltd 2021.
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    Development of Fast Charging Control Algorithm for Electric Vehicles
    (Institute of Electrical and Electronics Engineers Inc., 2022) Yadav, A.; Koorata, P.K.; Dastagiri Reddy, B.D.
    The rapid market integration of electric vehicles has resulted in an increase in the interest of fast charging technology. One of the major concerns associated with fast charging is safety of the operation. Fast charging involves effective communication between DC charger and battery management system through the charging control algorithm embedded in the vehicle controller unit. The development of such control strategy requires interdisciplinary cooperation between different participants. A lack of system understanding can lead to safety hazards. Here in this paper, we have developed a charging control strategy for CHAdeMO DC charger using model-based development which is a better method than conventional embedded C coding and its working is shown in a starter model of DC charger in STATEFLOW. © 2022 IEEE.
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    Crop pattern change and crop water requirement judgment using remote sensing and gis techniques: A research on tungabhadra dam right canal
    (Blue Eyes Intelligence Engineering and Sciences Publication, 2019) Yadav, A.; Hafeezunnisa; Kappadi, P.
    Agriculture is most important resources of any country worldwide which is a major renewable source and is dynamic. The study area selected was command area under Basavanna canal which is one of the canals to Tungabhadra river on right side bank. This selected canal for cropping pattern analysis has a command of 1240.00 hectare and is located at Vallabhpur, Bellary district. Basavanna canal has a designed discharge capacity of 125 cusecs for serving the cropping area. Every irrigation project has planned cropping pattern, the crop water requirement (CWR) for which is calculated based on Duty / Delta method. However due to growing population and increase demand for food products crop violation is found in every command leading to more irrigation. Remote Sensing (RS) and Geographical Information System (GIS) techniques have emerged as powerful tools for crop water management. Remotely sensed land use-land cover data was used for analysing the cropping pattern in the area and also to estimate the change in the cropping pattern. This study was performed using ArcGIS 9.3 and ERDAS 9 software. Crop water requirement was calculated using Modified Penman Equation for present cropping pattern. The study finds that, approximately 50% of water could be saved using modified Penmen method compared to crop water requirement calculated using Duty Delta method as adopted in project report and the same water may be diverted to meet other needs. © BEIESP.
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    Effect of exhaust gas recirculation rate on performance, emission and combustion characteristics of a common-rail diesel engine fuelled with n-butanol–diesel blends
    (Taylor and Francis Ltd. michael.wagreich@univie.ac.at, 2020) Lamani, V.T.; Yadav, A.; Gottekere, K.N.
    Increasing fears of fossil fuel attenuation and tough emission protocols compel the research community to explore alternative renewable fuels for diesel engines. Butanol is desirable among renewable fuels due to its properties favorable to diesel engines. This study focused on the suitability of exhaust gas recirculation (EGR) and optimum injection timing on the performance, combustion and exhaust emission characteristics of common-rail direct-injection (CRDI) engine fueled with n-butanol-blended diesel using experimental and computational fluid dynamics (CFD) simulation. Various EGR rates and injection timings are considered for different butanol–diesel blends (0, 10, 20 and 30%). Obtained simulation results are validated with experimental data and found to be in good agreement. For all EGR rates and blends, nitrogen oxide (NO) emission is reduced drastically, whereas carbon monoxide (CO) and soot emissions are decreased moderately, with increase in n-butanol–diesel blends. The CO and soot emissions increase with EGR rate due to oxygen deficiency as well. Brake thermal efficiency is reduced by approximately 1% for neat diesel (Bu0) with increase in EGR rates. Soot emission for Bu30 (15 ° Before top dead centre (BTDC) is decreased by 23, 25, 24 and 26% for 0, 10, 20 and 30% EGR rates, respectively, compared to Bu0 (12° BTDC). © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.
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    Numerical and experimental investigation of melting characteristics of phase change material-RT58
    (Elsevier Ltd, 2020) Yadav, A.; Donepudi, T.; Siddani, B.S.
    The present study is focused on experimental and numerical analysis of unconstrained melting of Paraffin wax-RT58 in a horizontally placed cylindrical container. After the validation of numerical model with experimental results, numerical analysis is extended to constrained melting to investigate the process. The experiments are carried out at constant wall temperature maintained on the lateral surface of the cylinder. The influence of initial sub-cooling and lateral surface temperature on the melting rate is investigated. The melting process is better analyzed by the melting phase front and temperature contours as time progresses. The results show that the melting rate decreases by increasing the initial sub-cooling, and increases with increasing lateral surface temperature of the cylinder. In unconstrained melting, heat transfer by conduction governs the melting process initially, but later it is restricted to only the bottom part of the cylinder as the solid PCM at a higher density sinks due to effects of gravity. Heat transfer in the upper half of the cylinder is dominated by natural convection set up in the liquid PCM. In constrained melting, pure conduction phenomenon exists only in the beginning, and later conjugate heat transfer occurs. When subjected to similar boundary conditions, PCM melt-time is lower in unconstrained melting than in constrained melting. A correlation between melt-time and Stefan number is also developed. © 2019 Elsevier Ltd
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    Enhanced thermo-hydraulic performance in a V-ribbed triangular duct solar air heater: CFD and exergy analysis
    (Elsevier Ltd, 2020) Nidhul, K.; Kumar, S.; Yadav, A.; Anish, S.
    Computational fluid dynamics (CFD) and exergy analysis are conducted to investigate the impact of secondary flow produced by V-ribs on the overall performance of a triangular solar air heater (SAH) duct. For a fixed relative rib pitch (Rp = 10) and relative rib height (Rh = 0.05), the effect of rib inclination (?) is studied using CFD technique for varying Reynolds number (5000 ? Re ? 20000). Based on the CFD simulation results, empirical correlations capable of predicting Nu and f with an absolute variance of 8.7%, and 4.7%, respectively, are developed. Employing these correlations, exergetic performance analysis is carried out. Maximum effectiveness parameter (?) of 2.01 is obtained for ? = 45° at Re = 7500. The exergy analysis reveals that the entropy generated is lower for the ribbed triangular duct compared to the smooth duct with maximum enhancement in exergetic efficiency (?ex) as 23% for ? = 45°. The study is extended for the rectangular duct to compare the performance with the ribbed triangular duct SAH (? = 45°). Results show that ribbed triangular duct SAH (? = 45°) is superior over various configurations of the ribbed rectangular duct SAH at higher mass flow rates. © 2020 Elsevier Ltd
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    Efficient design of an artificially roughened solar air heater with semi-cylindrical side walls: CFD and exergy analysis
    (Elsevier Ltd, 2020) Nidhul, K.; Yadav, A.; Anish, S.; Arunachala, U.C.
    Solar air heater (SAH) with semi-cylindrical sidewalls and W-baffles is analyzed for energy and exergy efficiency in the turbulent flow regime. Computational fluid dynamics (CFD) analysis is carried out for a fixed baffle inclination (?) and varying the relative baffle height (Rh = e/D) and relative baffle pitch (Rp = P/D) in the range 0.046–0.115 and 0.46–1.15, respectively. For Reynolds number (5000 < Re < 17,500), the numerical methodology is substantiated using experimental and theoretical correlations obtained from the literature. Smaller vortices near the sharp corners are removed by rounding the sharp edges, allowing the flow of fluid from inside and horizontal walls of the duct towards the semi-cylindrical sidewalls. This increases the overall turbulent kinetic energy. A peak augmentation of 3.24 and 4.03 times is obtained for Nusselt number (Nu) and friction factor (f), respectively, in contrast to conventional SAH. With a maximum enhancement of 127% in the effectiveness parameter relative to smooth SAH, this novel SAH design is evidently energy efficient. Based on CFD results, new correlations are developed in terms of Rh and Rp, which predicts the values with an absolute deviation of 4% and 7.4%, respectively. With lower exergy destruction, maximum enhancement in thermal and exergetic efficiency is obtained as 40.7% and 95.4%, respectively, for the proposed SAH relative to conventional SAH. Upon comparison with ribbed rectangular duct SAH configurations, the present design with semi-cylindrical side walls outperforms at all flow Re. © 2020 International Solar Energy Society
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    Comparative computational appraisal of supercritical CO2-based natural circulation loop: effect of heat-exchanger and isothermal wall
    (Springer Science and Business Media B.V., 2020) Thimmaiah, S.; Wahidi, T.; Yadav, A.; Mahalingam, A.
    Natural circulation loop (NCL) is a geometrically simple heat transfer device in which fluid flow occurs due to density gradient of loop fluid, induced by the temperature difference between the source and the sink. NCL has an inherent problem of instability caused by the combined effect of buoyancy, friction and inertia forces at varying operating conditions, and hence it requires an elegant solution of instability. The primary objective of the present work is to do a comparative study on the dynamic performance between two different configurations of NCL based on supercritical CO2, i.e. (i) NCL with isothermal heater and a cold heat-exchanger (ISO-CHX), and (ii) NCL with hot and cold heat-exchangers (HHX-CHX). To explore these NCLs, two-dimensional transient computational fluid dynamics studies have been carried out on the stability of supercritical CO2-based natural circulation loop. Results are obtained for different operating pressures and temperatures in the form of mass flow rate and velocity variation with respect to time. Results show the higher instabilities in both side heat-exchanger loop than an isothermal heater with heat-exchanger loop. At a lower rate of heat input at source in the HHX-CHX loop, the mass flow is bidirectional, whereas it is unidirectional in the ISO-CHX loop at all level of heat input. It is also observed that as pressure increases, flow instability also increases. Obtained results are validated with the published experimental and numerical data and found in good agreement. © 2020, Akadémiai Kiadó, Budapest, Hungary.
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    Combustion, performance and emission analysis of preheated KOME biodiesel as an alternate fuel for a diesel engine
    (Springer Science and Business Media B.V., 2020) Kodate, S.V.; Yadav, A.; Kumar, G.N.
    In the present work, karanja oil methyl ester (KOME) biodiesel is used in a compression ignition engine to find an alternative to diesel. The use of biodiesel in a CI engine leads to poor performance and high brake specific fuel consumption due to the higher viscosity and lower calorific value of biodiesel. This problem can be reduced by increasing the injection temperature of biodiesel or its blends to a certain temperature. In this study, working fuel is tested at preheating temperatures of 95 °C for various loading conditions (0, 25, 50, 75 and 100%). Effect of different KOME biodiesel–diesel blends (B0, B30, B50 and B100) on engine performance, combustion and emissions is studied at different loads. At higher temperature, the viscosity of the fuel decreases which leads to better combustion, improves the atomization as well as vaporization of fuel in a diesel engine, resulting in higher engine performance and lower emissions of CO and HC, with slight increment in NOX and CO2 emission compared to unheated neat diesel and biodiesel blends. The result shows that for 100% biodiesel (B100) at full load, BTE is improved by 9.1% compared to unheated case. Preheating of B100 fuel upto 95 °C at full load decreases the BSFC, CO and HC emission by 6.5%, 8.1% and 10.6%, respectively, compared to unheated case. © 2020, Akadémiai Kiadó, Budapest, Hungary.