Flow Patterns and Turbulence Structures in a Scour Hole Downstream of a Submerged Weir

Guan, Dawei; Melville, Bruce W.; Friedrich, Heide

doi:10.1061/(asce)hy.1943-7900.0000803

Cited by 102 publications

(49 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At time T 1 , return currents at the upstream side of the scour hole are clearly visible in the data (Figure 7a At time T 2 , the vertical structure of the flow is significantly different from that at time T 1 and far more uniform than what would be expected considering the relatively steep slopes at the upstream end of the scour hole (Kwoll et al, 2016). At T 1 , the depth-averaged streamwise flow velocity along the transect reduces proportionally to the streamwise increase in water depth, with an approximately 50% reduction of flow velocity from the Guan et al, 2014;Hoffmans & Booij, 1993).…”

Section: Vertical Velocity Componentmentioning

confidence: 85%

Observations and Analysis of the Horizontal Structure of a Tidal Jet at Deep Scour Holes

2018

View full text Add to dashboard Cite

Scour in the vicinity of a hydraulic structure may compromise its geotechnical stability or that of nearby structures. Much fundamental research has been dedicated to the understanding and prediction of these processes, in order to enable the efficient design of mitigation measures. While most of these efforts consider laterally uniform flows, nonuniformity is the rule rather than the exception. This study presents field observations near the storm surge barrier in the Eastern Scheldt estuary, The Netherlands, where significant scour holes have developed. The tidal flow through this semi‐open barrier exhibits characteristics of a shallow jet. A pronounced contraction of this jet toward the nearby scour hole during particular stages of the tidal cycle is revealed, attributed to potential vorticity conservation; the depth‐averaged vertical vorticity increases proportionally to the depth increase. Measurements show a vertically uniform velocity profile in the scour hole that is attributed to a reduction of the adverse pressure gradient due to the contraction, that suppresses boundary layer separation from the upstream slope of the scour hole. A positive feedback mechanism is thus revealed; lateral velocity gradients lead to relatively high near‐bed velocities in the scour hole which enhances erosion—causing an even stronger horizontal contraction—maintaining the scouring potential. If the upstream flow field is laterally uniform (observed around slack tide), horizontal contraction does not occur, and the boundary layer separates from the upstream slope. The scour depth will then tend to an equilibrium. The results infer the importance of the nonuniformity of the horizontal flow field.

show abstract

Section: Vertical Velocity Componentmentioning

confidence: 85%

Observations and Analysis of the Horizontal Structure of a Tidal Jet at Deep Scour Holes

2018

View full text Add to dashboard Cite

show abstract

“…Melville (2014) classified his method for different types of structures and presented a new equation based on Shields critical velocity to predict scour downstream of submerged weirs. Guan et al (2014a) carried out a series of experiments to investigate the flow patterns and turbulence in a scour hole downstream of a submerged weir. They showed that the turbulence structures ahead of the recirculation zone govern the dimensions of the scour hole.…”

Section: Introductionmentioning

confidence: 99%

Clear water scour at J-Hook Vanes in channel bends for stream restorations

Pagliara

Kurdistani

2015

Ecological Engineering

View full text Add to dashboard Cite

“…Velocity spectra were checked to ensure no bias due to Doppler noise. With similar quality-control protocols, an ADV has been used successfully to measure turbulence quantities in several other relevant investigations including flow fields downstream of submerged jets on solid aprons before and after scouring [4], and in a scour hole downstream of a submerged weir [5], for example.…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…Guan et al [5] concluded from flow-field measurements in the scour hole downstream of a submerged weir that a recirculation zone occurred above the upstream slope of the hole, and that turbulence structures in this region contributed to its size.…”

Section: Introductionmentioning

confidence: 99%

Effect of Submergence and Apron Length on Spillway Scour: Case Study

Hong

Biering

Sturm

et al. 2015

Water

View full text Add to dashboard Cite

Large-scale water resources systems are often managed by an integrated set of hydraulic structures that are vulnerable to wider ranges of discharge and tailwater elevation than envisioned in their original design due to climate change and additional project objectives such as fostering healthy ecosystems. The present physical model study explored the performance of a spillway structure on the Kissimmee River, operated by the South Florida Water Management District, under extreme conditions of drought and flooding with accompanying low and high tailwater levels for both gate-controlled and uncontrolled spillway flow conditions. Maximum scour depths and their locations for two different riprap apron lengths downstream of the spillway stilling basin were measured along with the complex flow fields prior to scour. Effects of tailwater submergence, type of spillway flow and riprap apron length on scour results are interpreted in terms of the measured turbulent kinetic energy and velocity distributions near the bed. OPEN ACCESSWater 2015, 7 5379

show abstract

Flow Patterns and Turbulence Structures in a Scour Hole Downstream of a Submerged Weir

Cited by 102 publications

References 23 publications

Observations and Analysis of the Horizontal Structure of a Tidal Jet at Deep Scour Holes

Observations and Analysis of the Horizontal Structure of a Tidal Jet at Deep Scour Holes

Clear water scour at J-Hook Vanes in channel bends for stream restorations

Effect of Submergence and Apron Length on Spillway Scour: Case Study

Contact Info

Product

Resources

About