IJE TRANSACTIONS C: Aspects Vol. 27, No. 12, (December 2014) 1823-1831 Please cite this article as: R. Mahmoudi, F. Ashrafzadeh, S. Tariverdilo, Introducing Padded Wall to Reduce Sloshing Induced Wall Pressure in Water Storage Tanks, International Journal of Engineering (IJE), TRANSACTIONS C: Aspects Vol. 27, No. 12, (December 2014) 1823-1831 International Journal of Engineering Journal Homepage: www.ije.ir Introducing Padded Wall to Reduce Sloshing Induced Wall Pressure in Water Storage Tanks R. Mahmoudi, F. Ashrafzadeh, S. Tariverdilo* Department of Civil Engineering, University of Urmia, Urmia, Iran PAPER INFO Paper history: Received 13 February 2014 Received in revised form 01 August 2014 Accepted 14 August 2014 Keywords: Sloshing Velocity Potential Function Padded Wall Water Storage Tank ABSTRACT Sloshing due to ground motion develops large pressure on the walls of water retaining tanks. This paper evaluates the efficacy of padded walls on the reduction of sloshing effects in rectangular water storage tanks subjected to ground motion. An analytical solution based on velocity potential function is provided to obtain the response of rigid and padded wall tanks in terms of wave elevation, maximum pressure on the tank wall and FFT spectrum of pressure on the water surface. In the proposed method, the boundary condition on the tank wall is kinetic representing pressure distribution on the tank walls against the usual methods with kinematic boundary condition only. The fluid is assumed to be inviscid, incompressible, and irrotational. Tanks with and without padded walls are evaluated under different types of ground motions classified as near source and far-field records. The results show noteworthy effect of the padded wall on reduction of above-mentioned sloshing responses. doi: 10.5829/idosi.ije.2014.27.12c.04 1. INTRODUCTION 1 Partially filled liquid storage tanks subjected to ground motion may be damaged under fluid fluctuation. This phenomenon is known as sloshing. Sloshing imposing large pressure on the tank wall could cause severe structural damages. Violent oscillation due to sloshing could occur in tanks with natural frequencies close to the excitation frequency. Many researchers have paid attention to sloshing response of liquid storage tanks. Abramson [1] studied sloshing in partially filled tanks. He used velocity potential function to evaluate the response of cylindrical tanks. Hwang et al. [2] used numerical and experimental methods to investigate sloshing in two and three- dimensional liquid containers. They found good agreement between the results of the two methods. Virella et al. [3] studied sloshing modes and pressure in rectangular tanks under harmonic excitation. They used linear wave theory (LWT) and nonlinear wave theory (NLWT) in ABAQUS software. Wang and Khoo [4] 1 *Corresponding Author’s Email: s.tariverdilo@urmia.ac.ir (S. Tariverdilo) employed finite element method (FEM) to study response parameters such as wave height and wall pressure in 2D tanks under random excitation. Tariverdilo et al. [5] investigated the importance of membrane and flexural stress in floating roofs of cylindrical liquid storage tanks. Shabani [6] studied the stress pattern in single deck floating roof with pontoon. Azhdari Moghaddam [7] investigated the design issues of surge tanks. Many researchers used different forms of baffles as sloshing suppression device. Isaacson and Premasiri [8] investigated damping in tanks with baffles as they cause flow separation and increase inherent material damping. Experimental studies were conducted on the rectangular tanks of various filling depth and different rolling frequencies with and without ring baffles by Akyildiz et al. [9]. Results demonstrated that the arrangement of baffles is effective in sloshing reduction. On the other hand, Cho and Lee [10] applied velocity potential based nonlinear FEM to investigate the effect of baffle height and width in two-dimensional rectangular tanks. Panigrahy et al. [11] conducted experimental studies on rectangular tanks with and without baffles. They used shaking table to excite a square tank with different