Estimation of scour dimensions below submarine pipelines is a vital step in designing offshore infrastructure.Extreme events like tsunami waves produce strong erosive forces below the underwater pipes,apt to create sc...Estimation of scour dimensions below submarine pipelines is a vital step in designing offshore infrastructure.Extreme events like tsunami waves produce strong erosive forces below the underwater pipes,apt to create scour holes,jeopardizing the safety of the structure.Despite the importance of this issue,previous studies have mainly focused on steady flow cases,and the scour pattern below submarine pipes induced by high-amplitude transient waves has rarely been investigated.This paper reports the results of 40 experimental runs on transient wave-induced scour below a model pipe in a laboratory flume under a variety of initial conditions.The variables included the bed particle size and gradation,initial water depth,wave height,and slope of the bed layer.Waves were generated by a sudden release of water from a sluice gate,installed in the middle of the flume.A pressure transducer data acquisition system was used to record the wave heights at different time steps.The results indicate that,with a shallower initial depth of flow,the scour depth is relatively large.It was also found that there exists a direct correlation between the induced wave height and the size of the scour hole.It was observed that,in clear water conditions,the size of the scour hole in coarse sediments is smaller,while in live-bed conditions,larger scour holes are created in coarser sediments.It was also observed that at high wave amplitudes,the live-bed conditions are dominant,and consequently the bed elevation is altered.展开更多
Through the fixed bed and live bed experiments, the factors influencing the turbulent width around bridge piers were analyzed, including approaching flow velocity, flow depth, flow angle, size of piers, shape of piers...Through the fixed bed and live bed experiments, the factors influencing the turbulent width around bridge piers were analyzed, including approaching flow velocity, flow depth, flow angle, size of piers, shape of piers and scouring. The experiments demonstrated that the turbulent width increased with approaching flow velocity, water depth and size of piers, kept constant with different flow angles, decreased as the shape of piers became smoother, and was less remarkably influenced by the scouring. Through applying the dimensional analysis method, the empirical expression was developed to calculate the turbulent width around bridge piers.展开更多
文摘Estimation of scour dimensions below submarine pipelines is a vital step in designing offshore infrastructure.Extreme events like tsunami waves produce strong erosive forces below the underwater pipes,apt to create scour holes,jeopardizing the safety of the structure.Despite the importance of this issue,previous studies have mainly focused on steady flow cases,and the scour pattern below submarine pipes induced by high-amplitude transient waves has rarely been investigated.This paper reports the results of 40 experimental runs on transient wave-induced scour below a model pipe in a laboratory flume under a variety of initial conditions.The variables included the bed particle size and gradation,initial water depth,wave height,and slope of the bed layer.Waves were generated by a sudden release of water from a sluice gate,installed in the middle of the flume.A pressure transducer data acquisition system was used to record the wave heights at different time steps.The results indicate that,with a shallower initial depth of flow,the scour depth is relatively large.It was also found that there exists a direct correlation between the induced wave height and the size of the scour hole.It was observed that,in clear water conditions,the size of the scour hole in coarse sediments is smaller,while in live-bed conditions,larger scour holes are created in coarser sediments.It was also observed that at high wave amplitudes,the live-bed conditions are dominant,and consequently the bed elevation is altered.
基金National West Communication Construction Technology Project (No.200432800040)
文摘Through the fixed bed and live bed experiments, the factors influencing the turbulent width around bridge piers were analyzed, including approaching flow velocity, flow depth, flow angle, size of piers, shape of piers and scouring. The experiments demonstrated that the turbulent width increased with approaching flow velocity, water depth and size of piers, kept constant with different flow angles, decreased as the shape of piers became smoother, and was less remarkably influenced by the scouring. Through applying the dimensional analysis method, the empirical expression was developed to calculate the turbulent width around bridge piers.
