Scour depth analysis beneath a submerged pipeline featuring a protective blade configuration

Abstract

The primary objective of the current research extends beyond the examination of the impact of the protective blade on the geometric features, namely length (L) and depth (H), of the scour hole formed beneath the cylindrical submerged pipeline. It encompasses the development of predictive equations to anticipate the characteristics of H and L under steady and clear water flow conditions. To achieve this objective, a total of 80 experiments were conducted, encompassing four distinct pipe diameters (D = 3.1, 4, 4.8, 6.2 cm) on sediments characterized by an average diameter of 0.72 cm. The tests involved the examination of four varying lengths of the protective blade (e = 1, 1.5, 2, and 2.5 cm) at five diverse locations (A1 to A5), systematically assessing its influence on the development of the scour hole. The findings of the forthcoming research underscored the pronounced influence of both the blade's configuration (position and length) particularly with smaller values of D. In the case of D = 3.1 cm and e = 2.5 cm, the installation of the blade downstream of the pipe (A5) resulted in a notable 70 % reduction in H. Contrarily, the results revealed an opposing effect on the L. The least increase in the L occurred when the blade was installed upstream of the pipe (A1), particularly with the smallest D and e. Additionally, two regression equations were developed to predict D and L using Fr=Vgy and eD. The performance assessment, conducted during both the calibration and verification stages of precise performance.

Keywords

• Pipeline scour
• Clear water scour
• Froude number
• Horizontal blade