Faculty Publications
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Item Parametric Study on Frequency Characteristics of Cylindrical Liquid Tanks(Springer, 2022) Nimisha, P.; Jayalekshmi, B.R.; Venkataramana, K.The response of liquid-storage tanks under seismic loading is a key research area. The study of free vibration characteristics is a prerequisite for understanding the dynamic behaviour of liquid tanks under seismic loading. Hence, the present study focuses on the analysis of different parameters that may influence the frequency characteristics of cylindrical liquid tanks. For this, a database of 560 three-dimensional cylindrical liquid tank models was developed by carrying out modal analysis using ANSYS Mechanical APDL software. The database was analysed with the aid of artificial neural networks and nonlinear regression analysis. Average deviations of 30% and 32% were observed for the impulsive frequency values estimated based on IS1893 (Part2):2014 and Eurocode-8, respectively, compared to the finite element results. Hence, modification coefficients were suggested with aspect ratio as the demarcating parameter and obtained a Pearson correlation coefficient of rXY > 0.9, between the predicted values of frequency and actual values. The predicted formulae reduced the deviations observed between the frequency estimated based on the codal expressions and those obtained from finite element analysis to 13% and 15%, corresponding to IS1893 (Part2):2014 and Eurocode-8, respectively. © 2022, The Institution of Engineers (India).Item Effective configuration of perforated baffle plate for efficient slosh damping in liquid retaining tanks under lateral excitation(Elsevier Ltd, 2022) Nimisha, P.; Jayalekshmi, B.R.; Venkataramana, K.Perforated baffle plates are used as an anti-slosh mechanism in various fields owing to the need for slosh suppression and weight reduction. However, there is an uncertainty in the selection of configuration of perforated baffle plate due to the several influencing parameters for slosh damping efficiency. Therefore, the present study focuses on the development of an efficient slosh damping configuration for the perforated baffle plate. For this, nonlinear dynamic analysis under seismic ground motions with different PGA/PGV ratios has been carried out in the time domain using the concepts of Computational Fluid Dynamics (CFD) in the numerical models of liquid tanks with perforated baffle plates of different configurations. The response of the system under impulsive and convective modes is analysed by observing the free surface elevation, hydrodynamic pressure, turbulence kinetic energy and turbulence eddy dissipation as the response parameters. The study developed an effective baffle configuration for efficient slosh damping, considering the various response parameters. © 2022 Elsevier LtdItem Slosh Damping in Rectangular Liquid Tank with Additional Blockage Effects under Pitch Excitation(American Society of Mechanical Engineers (ASME), 2022) Nimisha, P.; Jayalekshmi, B.R.; Venkataramana, K.The quantification and damping of slosh responses are significant due to the increasing demand for safety of the liquid-based applications under severe external excitation. Recently, the solid or perforated baffle plates have been used to damp the slosh response of the liquid. However, there is uncertainty in the selection of an effective configuration of the baffle plates. In addition, most of the studies reported the slosh response under surge excitation. Therefore, this study focuses on the slosh response of the rectangular tank fitted with perforated baffle plates of different configurations under pitch excitation. For this, the liquid sloshing is simulated using the concepts of computational fluid dynamics (CFD) using pressure-based solver in the time domain. A detailed parametric study is carried out to develop an effective configuration of the perforated baffle plates considering the area of perforations, interperforation distance, size of perforations, distance between the perforated baffle plates, alignment of perforations, and the vertical position of perforated baffle plate as the parameters. The slosh responses are observed in terms of free surface elevation, hydrodynamic pressure, turbulence kinetic energy, velocity streamlines, power spectral density corresponding to the free surface elevation and the free surface deformation. The study developed a "zig-zag blocking alignment"of perforations for effective slosh damping, with the solid area between the perforations being 50%-60% of the area of perforations. In addition, "single-acting range"and "damping range"are identified to pilot the positioning of the multiple baffle plates in a rectangular tank under pitch excitation. © 2022 by ASME.Item Numerical investigation of a novel flow damping device for mitigating liquid sloshing under bi-directional excitation(Springer Science and Business Media B.V., 2024) Jogi, P.; Jayalekshmi, B.R.Sloshing in liquid storage tanks (LSTs) poses a significant challenge, especially during the seismic events and necessitating the implementation of effective mitigation strategies. This study proposes a novel technique by introducing a flow-damping device (FDD) made up of singly curved cylindrical plates connected to a cylindrical stem. The FDD is designed to be placed inside the LSTs to dissipate seismic energy, thereby reducing sloshing effects. Numerical analysis was conducted using the Arbitrary Lagrangian and Eulerian formulations in ABAQUS to assess the efficiency of various FDD configurations in reducing sloshing displacements in LSTs. The liquid storage tank with and without FDDs, were subjected to uni and bi-directional ground motion records of Imperial valley and Northridge earthquakes with a scaled peak ground acceleration. The study revealed that the FDD configuration consisting of eight plates evenly distributed around the stem with two plates oriented towards each other is the most effective FDD in reducing the seismic response parameters. When the FDD is connected to the tank base and placed centrally inside the tank at a distance of one-sixth of the tank’s length from both ends of the tank wall achieved a maximum reduction of 52.64% in sloshing displacements and 47.99% in impulsive hydrodynamic pressures. These results emphasize the substantial effectiveness of the proposed FDD design in reducing sloshing and hydrodynamic effects in LSTs during seismic events. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.Item Innovative floating hybrid baffles for improved performance of liquid storage tanks under seismic excitations(Taylor and Francis Ltd., 2025) Jogi, P.; Jayalekshmi, B.R.Liquid storage tanks (LSTs) are highly susceptible to sloshing under dynamic motion, which can compromise their structural stability. This study introduces novel floating wooden and hybrid baffles with a rubber-encased wooden core, offering enhanced energy dissipation and durability. Unlike fixed baffles, their floating design allows for adaptation to changes in liquid levels. Numerical simulations were conducted using ABAQUS to evaluate the performance of these baffles in reducing sloshing-induced responses. The LST, with and without baffles, was subjected to Imperial Valley and Northridge ground motions. Three baffle configurations with varying widths were analyzed for reducing liquid sloshing, hydrodynamic pressures, and enhancing energy dissipation at different liquid depths. The results indicate that the medium-width hybrid baffles reduce the sloshing heights by 51% while maintaining sufficient fluid flow. Hybrid baffles significantly reduced convective pressures by 57% and showed superior energy dissipation than wooden baffles. These findings confirm their effectiveness in controlling liquid sloshing. © 2025 Informa UK Limited, trading as Taylor & Francis Group.Item Sloshing mitigation in liquid storage tanks using vertical floating wooden baffles(Springer, 2025) Jogi, P.; Jyothish, S.S.; Jayalekshmi, B.R.Liquid storage tanks (LSTs) are essential infrastructure but susceptible to failure due to liquid sloshing during seismic events. This sloshing generates additional hydrodynamic forces, which can impose pressure on the tank walls. Conventional methods to mitigate sloshing often rely on rigid internal structures, which can be expensive and inflexible. To overcome these challenges, the present study investigates the effects of lightweight floating wooden baffles that adapt to the liquid level within the tanks, offering a more flexible and cost-effective solution. This research aims to assess the performance of vertical floating wooden baffles in mitigating sloshing within liquid storage tanks. Numerical analysis was conducted on 3D ground-supported rectangular tanks with seven different baffle configurations, including both solid and porous designs, using the arbitrary Lagrangian–Eulerian (ALE) approach in ABAQUS. The models were subjected to horizontal seismic ground motion records from the Imperial Valley and Northridge earthquakes. Critical parameters such as sloshing wave height, hydrodynamic pressures and kinetic energy in the LST were analysed. The findings reveal that porous wooden baffles positioned near the tank walls are particularly effective in reducing sloshing and the associated hydrodynamic forces, offering a cost-efficient solution to enhance the safety of LSTs during seismic events. © Indian Academy of Sciences 2025.