Faculty Publications
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Item Experimental Study on Liquid Sloshing Dynamics in a Sway Excited Rectangular Tank(Springer Science and Business Media Deutschland GmbH, 2024) Sahaj, K.V.; Shri, S.; Nasar, T.An experimental shake table program is performed to explore the hydrodynamic behavior of liquid sloshing phenomena in a partially filled rectangular tank of 1:43 scaled tank subjected to sway excitation. Three different aspect ratios (hs/l, liquid depth, hs to the length of the tank, l) of 0.163, 0.325 and 0.488 which corresponds to 25%, 50% and 75% fill depths are considered. Excitation parameters such as frequencies ranging from 0.45 to 3.2 Hz which encompasses up to fifth mode of sloshing frequency and amplitudes of 4 and 8 mm are considered. An experimental setup is designed and devised to measure the sloshing force by using ballast mass concept. The experimental parameters such as run-up of sloshing oscillation, sloshing force and spectral energy are discussed. Experimental results of sloshing oscillation are compared with the numerical works of Nasar et al. (J Nav Archit Mar Eng 9:43–65, 2012). The present study reveals that the effect of excitation on sloshing oscillation is more pronounced near first mode of resonance and insignificant at off-resonance conditions. The effect of excitation amplitude on the fill level is pronounced in the order of 50, 25 and 75% fill levels on sloshing oscillation, sloshing force and spectral energy. The sloshing force is found to be about 9.32, 26.03 and 26.43 N for the excitation parameters of forcing frequency (f) that equals to first mode sloshing frequency (f1) and amplitude of excitation A = 8 mm. The sloshing tank with 75% fill depth experiences more sloshing force on its containment than 25 and 50% fill depths. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Sloshing dynamics and performance of porous baffle arrangements in a barge carrying liquid tank(Elsevier Ltd, 2019) Nasar, T.; Sannasiraj, S.A.An experimental investigation is conducted to explore the effectiveness of porous baffles placed at l/3 and 2l/3 in the sloshing tank. A tank aspect ratio, hs/l of 0.488 which corresponds to 75% filled condition is considered. The sloshing tank is kept inside the freely floating barge and subjected to regular beam sea waves. A wave height of 0.1 m and excitation frequencies ranging from 0.45 Hz to 1.54 Hz is adopted. Baffles with three different porosities of 15%, 20.2% and 25.2% are used. The effectiveness of baffles placed at l/3 and 2l/3 is explored on comparison with the performance of single porous baffle kept at l/2 and a solid submerged baffle place at l/2. Sloshing dynamics for the baffles placed at l/3 and 2l/3 and barge responses are also discussed. © 2019 Elsevier LtdItem Performance assessment of porous baffle on liquid sloshing dynamics in a barge carrying liquid tank(Taylor and Francis Ltd., 2021) Nasar, T.; Sannasiraj, S.A.; Sundar, V.A comprehensive experimental work is done to investigate sloshing dynamics in a partially liquid-filled baffled tank, equipped with a floating barge. An aspect ratio(hs /l, liquid depth, hs to length of tank, l) of 0.488 (above critical fill level), which corresponds to 75% fill level, is considered. The barge was subjected to regular wave excitations with a wave height of 0.1 m and frequencies ranging from 0.45Hz to 1.54Hz under beam sea condition. In addition, porous baffles are placed inside a rectangular tank to study its effectiveness in reducing the sloshing energy. Three different porosities of 15%, 20.2% and 25.2% at l/2 are considered. The effectiveness of baffles is explored and the salient results for a single porous baffle are discussed. It is learnt that the effect of baffles on sway and roll responses is significant, whereas it is insignificant on heave. Porous baffles are effective in suppressing the sloshing oscillation in the vicinity or at wave excitation, fw =f 1, whereas the sloshing is amplified at fw =f 2 and fw =f 3 due to the resonance condition of modified natural frequencies. © 2020 Informa UK Limited, trading as Taylor & Francis Group.Item Sloshing Dynamics in Sway Excited Rectangular Scaled Tanks; 横荡激励下矩形缩比罐中的液体晃动力学(Editorial Board of Journal of Harbin Engineering, 2023) Sahaj, K.V.; Shri, S.; Nasar, T.The present paper presents the sloshing oscillation behaviour and sloshing force in three different tanks of model scales of 1:86, 1:57 and 1:43. The rectangular tank is mounted on shake table, to study the scale effect of sloshing with sway excited motion. The tests are carried out for the aspect ratio (hs/l, where hs liquid depth and l is the length of the tank) of 0.162 5, 0.325, and 0.487 5 which represents 25%, 50% and 75% of liquid fill levels, respectively. Seventeen excitation frequencies ranging from 0.456 6 Hz to 1.975 7 Hz are considered, which covers up to the fifth sloshing mode. The sloshing oscillations occurs in the longitudinal axis when subjected to sway excitations. An experimental setup is designed and devised to measure sloshing force by the concept of ballast mass. The inertia forces are measured by load cells and sloshing oscillation time histories are measured by capacitance probes. It is found that violent sloshing is experienced for 50% filled condition irrespective of scaled tanks, excitation amplitudes and excitation frequencies. The sloshing force is maximum in 1:43 scaled tank than other scaled sloshing tanks irrespective of the excitation frequency and amplitude for 50% fill level. Based on the experimental observations and analysis of results, it is concluded that proportionate volume of water and tank size decides the severity of sloshing in the partially filled tanks. © 2023, Harbin Engineering University and Springer-Verlag GmbH Germany, part of Springer Nature.