Faculty Publications
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Item CFD investigation of unsteady three-dimensional savonius hydrokinetic turbine in irrigation channel with varying positions for hydro power application(American Institute of Physics Inc., 2021) Shashikumar, S.; Hindasageri, V.; Madav, M.Savonius turbines are a drag driven device, and it has high starting torque. It is a vertical axis turbine and installed in small irrigation channels to utilize the hydrokinetic energy available. Since the density of water is more and the flow of water in the channel is constrained to one direction is the advantage for a vertical axis turbine as it reduces the yaw control mechanism. In the present work, a three-dimensional conventional Savonius turbine modeled and meshed in ANSYS Fluent and unsteady transient simulations are carried out using a sliding mesh technique. The computational simulations were carried out at three different positions to analyze the effect of placing a turbine blade in the high depth of water using a conventional Savonius turbine blade with an aspect ratio of 0.7 and 0.0 overlap ratio. The turbulence model used for CFD simulation is the k-ω SST model, and the results found that the maximum coefficient of torque and coefficient of power of 0.22 and 0.17 at a tip speed ratio of 0.7 and 0.9 respectively. © 2021 Author(s).Item Studies on application of vertical axis hydro turbine for sustainable power generation in irrigation channels with different bed slopes(Elsevier Ltd, 2021) Shashikumar, S.; Honnasiddaiah, R.; Hindasageri, V.; Madav, V.The present work is carried out to study the performance of a Savonius rotor for small-scale hydropower generation. It has been observed that some of the irrigation channels available in the rural areas are having enough bed slope to generate kinetic energy, which can be harnessed through a Savonius rotor. An in-house fabricated scale-down model of the Savonius rotor is tested at an inclination of the re-circulating indoor multipurpose tilting flume at 0°, 0.5°, 1.0°, 1.5° and 2.0° to determine performance under controlled conditions. It is observed that at the tip speed ratio of 0.92 and channel inclination of 0.5° compared to 0° inclination, the coefficient of power and coefficient of torque improved to 40% and 10%, respectively. Furthermore, it is found that the torque and power developed by the turbine are maximum at a bed slope of 2.0° owing to the maximum available energy. © 2020 Elsevier LtdItem Numerical investigation of conventional and tapered Savonius hydrokinetic turbines for low-velocity hydropower application in an irrigation channel(Elsevier Ltd, 2021) Shashikumar, S.; Vijaykumar, H.; Madav, V.In the present work, computational fluid dynamics simulation was carried out using ANSYS Fluent to study the performance of conventional and tapered turbine blades for hydrokinetic power generation. The sliding mesh technique is used to study the influence of taper on conventional Savonius turbine using the SST k-? turbulence model and performance parameters were determined. The geometric parameters used in the present simulation for conventional and tapered turbine blades are aspect ratio and overlap ratio of 1.0 and 0.0. The inlet velocity and depth of water used for present simulation are 0.5 m/s and 103.6 mm for both conventional and tapered turbine blades. The results show that a 5% increase in the performance of a conventional turbine as compare to tapered turbine blade with a taper angle of 5°. The value of maximum coefficient of power for conventional Savonius turbine blade is 0.21 with a tip speed ratio 0.9. The flow field around the conventional and tapered turbine blades at different angular positions are analysed. It was found that there is a loss of energy at the exit side of the advancing blade for the case of tapered turbine, that leads to 5% reduction of performance as compared to the conventional turbine. © 2020 Elsevier LtdItem Experimental and numerical investigation of novel V-shaped rotor for hydropower utilization(Elsevier Ltd, 2021) Shashikumar, S.; Honnasiddaiah, R.; Hindasageri, V.; Madav, V.Hydrokinetic technologies harvest renewable power by harnessing the kinetic energy of water from free-flowing rivers, streams, dam head/tailrace and irrigation channels. Savonius rotor is one of the simple and low-cost vertical axis drag type devices used for the extraction of hydrokinetic power. The main limitation of Savonius hydrokinetic turbine is its low efficiency due to negative torque developed by the returning blade without augmentation techniques. In this paper, an experimental investigation is carried out in a multipurpose tilting water flume using V-shaped rotor blade profiles by maintaining a fixed V-angle of 90°, varying length of V-edges, arc radius and with a constant aspect ratio of 0.7. The simulations were carried out using commercial software, ANSYS Fluent. From the experimental and numerical results, it was found that, the optimum blade profile (V4) has developed a maximum coefficient of power 0.22 and 0.21 respectively, at a tip speed ratio 0.87. It was found that, the maximum coefficient of power of optimal V-shaped blade profile (V4) is 19.3% higher than the semi-circular blade profile. © 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 AND EXPERIMENTAL INVESTIGATION INTO THE EFFECT OF LEADING-EDGE PROTUBERANCES ON THE AERODYNAMIC PERFORMANCE OF WIND TURBINE(Begell House Inc., 2025) Sathyabhama, A.; Sinha, R.K.; Reddy, C.J.In this paper, the numerical and experimental analysis of the effect of leading-edge protuberances on the performance of small horizontal axis wind turbines (SHAWT) at low Reynolds number was carried out. The wind turbine blades were designed using the blade element momentum theory (BEMT) with wake rotation. The E216 profile was chosen over other airfoils because, in low Reynolds number flow conditions, it gives a high lift-to-drag ratio. The tubercle shapes employed for the study are slot, triangular, and sinusoidal, and their effects on the performance of wind turbine were compared with baseline turbine as well as among themselves. The flow behavior and the influence of pitch angle on the performance of baseline wind turbine were investigated. The numerical simulations were conducted in ANSYS FLUENT R2021, and the experiments carried out in a low-speed wind tunnel were used to validate the results. The numerical equations were solved using a three-dimensional Reynolds-averaged Navier-Stokes equation with a shear stress turbulence (SST) k-? turbulence model. The output power, torque, and coefficient of power (CP) values for the baseline turbine increased up to 25° pitch angle and afterwards, a decline was seen. The optimum tip-speed ratio (TSR) was also investigated and found to be 2.67. The pitch angle 25° provides the greatest improvement among all pitch angles examined for the same blade profile. Hence, for the study of different-shaped tubercles (triangular, sinusoidal, and rectangular slot) pitch angle of 25° was considered. Sinusoidal tubercles show a greater lift-to-drag (CL /CD) ratio than baseline wind turbines, although there is no substantial difference in CP. Furthermore, the CL /CD for triangular and slotted tubercles is more significant than that of the baseline wind turbine, as is the CP. When all three tubercles are compared, the slot has the highest CP, while the sinusoidal wind turbine has the highest CL /CD. © 2025 by Begell House, Inc.