Experimental investigation into the effects of reduced vertical centre of gravity of an articulated concrete mattress in current flow

An articulated concrete mattress model has been utilised to investigate the effects of reduced vertical centre of gravity on the stability of a 400 series block. Experimental testing was conducted at the AMC CWC, Beauty Point. To determine the effects that a reduced centre of gravity has on stability, the 3 by 3 articulated concrete mattress model was subject to pure uniform current flow. The subsequent forces were analysed with a six degree of freedom underwater force sensor. In order to gain a range of real world scenarios, the experimental model was tested at six flow angles ranging from -15 degrees through to 60 degrees, at 15 degree increments. Additionally, five fluid velocities starting at 0.6 m/s through to 1.4 m/s, at 0.2 m/s increments were investigated. These results explain how the inversion of a 400 series block increases its hydrodynamic coefficients and subsequently decreases its stability performance in current flow. Ultimately, this study provides experimental information for the installation of 400 series articulated concrete mattresses in the inverted orientation.