Fluid Pressures in Partially Liquid-Filled Horizontal Cylindrical Vessels Undergoing Impact Acceleration

An experimental investigation has been carried out to study the fluid pressures in partially liquid-filled vessels when they are suddenly accelerated by impact along the longitudinal axis. The experiments were conducted with three horizontal cylindrical tanks of different length-to-diameter ratios of L/D = 6.0, 3.5, 2.0. The tanks were filled with water at ambient pressure and temperature and were accelerated using a large steel impact hammer. Internal tank wall pressures caused by the acceleration were measured with transient pressure transducers. Six types of pressure-time histories have been observed and results indicated that the pressure profile changes with fill level and transducer location. The peak pressures on the end of the tank are strongly affected by the fill level and the tank length-to-diameter ratio L/D. A modal change in the behavior of liquid movement has been found around fill level h/D = 0.95. For fill levels h/D above 0.95, the pressure in the tanks acted like either a water hammer or an accelerated fluid column, depending on the duration of the impact relative to the pressure wave transit time. For the fill levels with h/D below 0.95, liquid sloshing activity was involved and the pressure at the end of the tank was a function of the liquid dynamic pressure. This modal change also caused the location of maximum peak pressure to move from the impact end of the tank to the tank top. In some cases the pressure on the tank top was two times larger than that at the tank impact end. The maximum pressure observed from the tests was on the top of the tank. This modal change may have some significance in some transportation applications.