Faculty Publications
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Item Numerical and experimental investigation of modified V-shaped turbine blades for hydrokinetic energy generation(Elsevier Ltd, 2021) Shashikumar, S.; Madav, V.The Savonius rotor is one of the simple and cost-effective vertical axis drag type devices for hydropower generation. The main drawback of the Savonius hydrokinetic turbine is its low performance due to negative torque developed by returning blade profile. In this paper, the performance of modified V-shaped rotor blades with different V-angles ranging from 90° to 40°, by maintaining fixed edge length, arc radius and aspect ratio of 0.7 is investigated. The numerical analysis is carried out to estimate the optimum V-angle by maintaining 70 mm depth of water with an inlet velocity of 0.3090 m/s. The numerical study revealed that, for 80° V-angle rotor blade profile, the maximum coefficient of power was found to be 0.2279 at a tip speed ratio of 0.9. This optimum V-angle model was used for experimental analysis to study the effect of aspect ratio ranging from 0.7 to 1.75 using top, middle and bottom plates by maintaining 140 mm depth of water and inlet velocity of 0.513 m/s. The rotor blade with two endplates and one middle plate with an aspect ratio of 1.75 has shown a significant increase of performance by 86.13% at a tip speed ratio of 0.86 as compared to turbine blade with two endplates. © 2021 Elsevier LtdItem Performance analysis of novel V-shaped turbine blade profile by three-dimensional numerical investigations with varying overlap ratios for hydropower application(Elsevier Ltd, 2022) Shashikumar, C.M.; Madav, V.In the present paper, three-dimensional numerical simulations were carried out to examine the influence of the overlap ratio between the two straight edges on the advancing and returning blades of the novel V-shaped rotor blade profiles using the sliding mesh technique. The performance parameters were computed with respect to the tip speed ratio. The findings show that the coefficient of torque and power for the novel V-shaped turbine blade is maximum for the zero-overlap ratio compared to the turbine blade, with an overlap ratio ranging from 0.05 to 0.3. The blade profiles' flow field was visualized at different angular positions, and various significant zones developed during the turbine blade rotation were captured and analyzed. The new overlapping jet developed between the two straight edges of the advancing and returning blade profiles as the overlap ratio varies from 0.05 to 0.3. Therefore, the turbine's performance is reduced due to the development of an overlap jet as it travels parallel to the straight edges of the blade profile and does not impact the rear side of the returning blade profile. © 2022 Elsevier LtdItem Numerical studies on the performance of Savonius hydrokinetic turbines with varying blade configurations for hydropower utilization(Elsevier Ltd, 2024) Shanegowda, T.G.; Shashikumar, C.M.; Gumtapure, V.; Madav, V.Hydrokinetic turbines harness the kinetic energy of flowing water to generate sustainable power, offering a promising avenue for clean and renewable energy. An effective turbine design is necessary for optimizing power extraction even in scenarios with minimal head. Among the various hydrokinetic turbine designs, the Savonius hydrokinetic turbine holds prominence. Over the past century, numerous studies have aimed to refine the design of the Savonius rotor, yet there remains no consensus on the ideal configuration for these turbines. Addressing this, the current study introduces a novel approach with detailed 3D transient simulations to enhance the water turbine performance via blade modifications, transitioning from traditional analyses that primarily focus on wind turbines. This research develops and analyzes five unique turbine geometries, each varying in blade number, diameter, and angular positions. A detailed numerical analysis was conducted using the sliding mesh technique to assess their impact on turbine efficiency and output, using an inlet water velocity of 0.5 m/s and a tip speed ratio ranging from 0.7 to 1.3. Findings indicate that a two-blade turbine configuration achieves the highest torque coefficient of 0.295, which is 2.41 times higher than that of a four-bladed design with equal blade diameter at a tip speed ratio of 0.7. It also reaches a maximum power coefficient of 0.217, marking a 155 % increase over four-bladed designs with equal blade diameter at a tip speed ratio of 0.9. © 2024 Elsevier LtdItem Comprehensive analysis of blade geometry effects on Savonius hydrokinetic turbine efficiency: Pathways to clean energy(Elsevier Ltd, 2024) Shanegowda, T.G.; Shashikumar, C.M.; Gumtapure, V.; Madav, V.The rising global demand for clean and renewable energy has intensified interest in hydrokinetic energy harvesting, with Savonius turbines gaining attention due to their simplicity and low cost. While numerous studies have focused on refining blade designs for wind turbines, limited research has been conducted on water turbines to identify the best design. This study investigates the effect of blade geometry on the efficiency of Savonius hydrokinetic turbines to identify the optimal configuration. Three new blade designs were tested, incorporating inner blades and varying blade numbers. These designs were experimentally evaluated to identify the optimal turbine configuration for maximum efficiency, and the findings were then validated through numerical studies. Rotational analysis was conducted to investigate torque variations across a full turbine rotation from 0° to 360°, and flow characteristic analysis was performed by utilizing pressure and contour plots at critical positions, including 0°, minimum torque coefficient (CT Min), and maximum torque coefficient (CT Max). Results indicate that the 2-blade Savonius turbine achieved the highest efficiency, with a maximum torque coefficient of 0.29 and a power coefficient of 0.22. It demonstrated 63.5 % greater power efficiency compared to the 3-Blade Savonius Turbine, 2.65 times greater than the Segmented Quarter Savonius Turbine, and 2.26 times greater than the Concentric Arc Savonius Turbine. These findings highlight the importance of blade geometry optimization in improving the performance of Savonius turbines for efficient hydrokinetic energy generation. © 2024 The AuthorsItem Numerical analysis of Savonius hydrokinetic turbine performance in straight and curved channel configurations(Elsevier Ltd, 2025) T G, S.; Shashikumar, S.; Gumtapure, V.; Madav, V.The global shift towards renewable energy has driven research into efficient hydrokinetic energy harvesting, particularly using Savonius turbines for their simplicity and adaptability to low-flow environments. While previous studies have focused primarily on straight channels, the impact of channel bends, commonly found in agricultural canals, rivers, and irrigation channels, remains underexplored. The present 3D transient numerical study addresses this gap by investigating the performance of Savonius hydrokinetic turbines in channels with 30°, 60°, and 90° bends, evaluating their efficiency under varying flow conditions. The research aims to evaluate the impact of these channel bends on key performance parameters such as the tip speed ratio (TSR), torque coefficient (CT) and power coefficient (CP), supported by detailed pressure and velocity contour analyses. The turbine positioned in the 30° bend emerged as the most efficient configuration, achieving a CTmax of 0.29 at 0.7 TSR and CPmax of 0.24 at 1.0 TSR. The 60° and 90° bends exhibited efficiency reductions of 15 % and 30 %, respectively, due to adverse pressure gradients and increased turbulence. Velocity contour plots demonstrated reduced wake regions and optimized flow reattachment for the 30° bend, while pressure contour analysis indicated lower drag forces on the advancing blades. This study highlights the potential of using Savonius turbines in agricultural channels, recommending the 30° bend as the optimal channel configuration to maximize turbine efficiency, providing a sustainable solution for energy generation in rural and low-flow environments. © 2025