Analysis of lateral sloshing forces within road containers with high fill levels

Abstract

This paper describes the experimental assessment of lateral sloshing forces developed within scaled road tankers as a function of fill level and container shape, focusing on high fill levels (from 90 to 98 per cent) and three container shapes (oval, modified oval, and circular). The purpose of the study was to estimate the effect of sloshing forces on the lateral stability of tank trucks when operating almost fully loaded. Water was used as the working fluid while the lateral dimensional characteristics of the containers represented a reduction scale of road tankers in the range of 1:5. Containers were subjected to a lateral excitation imparted by a sinusoidal electromagnetic shaker that moved a wheeled container/support assembly at a range of frequencies. The residual after-perturbation sloshing forces were measured by means of a force transducer connected to the shaker ram, and recorded for analysis. For the 98 per cent fill level, normalized sloshing forces were found to represent up to 4 per cent of the total liquid weight. Application of these normalized forces to actual size tank trucks further suggests that the rollover threshold acceleration of a rigidly suspended tank truck, due to sloshing, can be reduced by 2 per cent for the 98 per cent fill level, and around 10 per cent for the 90 per cent fill level. These already significant reductions in the roll stability of tank trucks would be more severe for a spring suspended vehicle, thus rationalizing the rollover trend of such vehicles. The use of longitudinal sloshing suppressors is strongly recommended.