Flow dynamics in the vicinity of a gravel embedded vertical retaining wall: conditions corresponding to the initial stages of local erosion

Heydari, Nasser; Diplas, Panayiotis

doi:10.1007/s10652-019-09715-8

Cited by 4 publications

(3 citation statements)

References 30 publications

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“…This is consistent with the results obtained from the Q-criterion (Figure 12). The distribution of TKE* on the plane that is perpendicular to the main flow direction, located near the leading edge of the retaining wall is in accordance with observations of Heydari and Diplas [19] (not shown here for the sake of brevity). More specifically, it was observed that a region of high TKE* emanates from the leading edge of the protrusion and extends to the channel bed.…”

Section: Bimodal Oscillations Of the Jv1supporting

confidence: 90%

“…To the best of our knowledge, this is the first time that the POD method is applied on 3D velocity data within a 3D measurement area near a longitudinal flow obstruction. Combining the observations and results of this study with those reported by Heydari and Diplas [19], we can get a more complete understanding of the flow dynamics in the vicinity of a longitudinal wall obstruction, which influence local scour and the integrity of this structure.…”

Section: Introductionsupporting

confidence: 65%

“…Their findings suggest that the final geometry of the scour hole is attributed to the combined effects of the JV system and the wake vortex. Recently, Heydari and Diplas [19] employed a steroscopic PIV (SPIV) system, consisting of two cameras, to examine the underlying turbulent flow characteristics near the leading edge of a longitudinal protrusion installed over a gravel bed. The measurement plane in that study was perpendicular to the main flow direction.…”

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Turbulent Flow Characteristics Near the Leading Edge of a Longitudinal Structure in the Presence of an Inclined Channel Bank

Heydari

Diplas

2022

Water

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The present work investigates turbulent flow structures and behavior near the leading edge of a longitudinal flow obstruction in an open channel with an inclined bank. A volumetric particle image velocimetry (VPIV) was employed to collect velocity data. The results indicate that a relatively moderate channel bank angle (θ=28∘) does not prevent the formation of a junction vortex (JV) system. Indeed, it is found that the JV system develops over the channel bank and extends to the leading edge of the flow obstruction. It is demonstrated that the main factor that strengthens the primary junction vortex (JV1) at the tip of the protrusion is the pronounced downward flow. The probability density functions (pdfs) of the velocity fluctuations specify that the JV1 oscillates aperiodically between the so-called zero-flow and back flow modes. This explains the amplification of TKE at its core. It is shown that the velocity difference between the peaks of the pdf increases from over the channel bank towards the tip of the flow obstruction. The aperiodic behavior of the JV1 is confirmed via the proper orthogonal decomposition (POD) technique. Specifically, it is demonstrated that the leading POD modes, associated with the JV system, contain lower energy content compared to periodic flows. The time-averaged vertical vorticity field verifies the presence of a tornado like vortex structure near the upstream face of the retaining wall. Finally, the results suggest that the largest bed shear stress values in the mean flow are located near the tip of the protrusion.