Coherent structures in flow over hydraulic engineering surfaces

Adrian, Ronald J.; Marušić, Ivan

doi:10.1080/00221686.2012.729540

Cited by 121 publications

(102 citation statements)

References 97 publications

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“…Nezu 2005) that indicate the presence of long rotational motions resembling VLSMs in pipes, closed channels and boundary layers. A fairly comprehensive review of long rotational motions that are occasionally reported for OCFs can be found in Adrian & Marusic (2012). They stated that the 'close relationship between meandering VLSMs of turbulence structure research and the long cellular motions of open-channel flow research is impossible to ignore.…”

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confidence: 99%

Very-large-scale motions in rough-bed open-channel flow

2017

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Long-duration particle image velocimetry measurements in rough-bed open-channel flows (OCFs) reveal that the pre-multiplied spectra of the streamwise velocity have a bimodal distribution due to the presence of large-and very-large-scale motions (LSMs and VLSMs, respectively). The existence of VLSMs in boundary layers, pipes and closed channels has been acknowledged for some time, but strong supporting evidence for their presence in OCF has been lacking. The data reported in this paper fill this gap. Length scales of the LSMs and VLSMs in OCF exhibit different scaling properties; whereas the streamwise length of the LSM scales with the flow depth, the VLSM streamwise length does not scale purely with flow depth and may additionally depend on other scales such as the channel width, roughness height or viscous length. The transverse extent of the LSMs was found to increase with increasing elevation, but the VLSM transverse scale is anchored around two flow depths. The origin and nature of LSMs and VLSMs are still to be resolved, but differences in their scaling suggest that VLSMs in rough-bed OCFs form independently rather than as a spatial alignment of LSMs.

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confidence: 99%

Very-large-scale motions in rough-bed open-channel flow

2017

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“…In this method, the Reynolds stresses were partitioned into four events: ejection, sweep, inward interaction, and outward interaction events (Adrian and Marusic 2012;Nezu 2005) (Fig. 4).…”

Section: Secondary Currentsmentioning

confidence: 99%

Turbulence study in the vicinity of piano key weir: relevance, instrumentation, parameters and methods

Tiwari

Sharma

2015

Appl Water Sci

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This research paper focuses on the need of turbulence, instruments reliable to capture turbulence, different turbulence parameters and some advance methodology which can decompose various turbulence structures at different levels near hydraulic structures. Small-scale turbulence research has valid prospects in open channel flow. The relevance of the study is amplified as we introduce any hydraulic structure in the channel which disturbs the natural flow and creates discontinuity. To recover this discontinuity, the piano key weir (PKW) might be used with sloped keys. Constraints of empirical results in the vicinity of PKW necessitate extensive laboratory experiments with fair and reliable instrumentation techniques. Acoustic Doppler velocimeter was established to be best suited within range of some limitations using principal component analysis. Wavelet analysis is proposed to decompose the underlying turbulence structure in a better way.

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Section: Introductionmentioning

confidence: 99%

“…In the last few years, a number of papers have reviewed developments in hydraulics and ecohydraulics, as well as the prospect for future research directions [Nezu, 2005;Adrian and Marusic, 2012;Nepf, 2012]. In addition, experimental and eddy-resolving numerical work has highlighted the important role played by coherent flow structures in a variety of fluvial processes [Adrian and Marusic, 2012;Venditti et al, 2013] and more work could be done to link these to the recent developments in our understanding of boundary layer fluid mechanics [Ganapathisubramani et al, 2005;Marusic et al, 2010;Guala et al, 2011]. Reviews of the potential for eddy-resolving numerical methods in the fluvial sciences have also appeared [Keylock et al, 2012a;Constantinescu, 2014;Stoesser, 2014], highlighting the techniques available and the advances in knowledge necessary in order to formulate methods tailored to hydraulics and geomorphological applications [King et al, 2012;Schmeeckle, 2014].…”

Section: Introductionmentioning

confidence: 99%

Flow resistance in natural, turbulent channel flows: The need for a fluvial fluid mechanics

Keylock

2015

Water Resources Research

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In fluvial environments, feedbacks among flow, bed forms, sediment, and macrophytes result in a complex fluid dynamics. The assumptions underpinning standard tools in hydraulics are commonly violated and alternative approaches must be formulated. I argue that we should question the assumption that classical notions in fluid mechanics provide the foundations for the techniques of the future. Recent work on turbulent dissipation, interscale modulation of the dynamics, intermittency, and the role of complex forcings is discussed. An agenda for future work is proposed that involves improving our characterization of complex forcings and developing better understanding of the behavior of the velocity gradient tensor in complex, fluvial environments. This leads to the formulation of modeling tools relevant to fluvial fluid mechanics, rather than a reliance on methods developed elsewhere. One avenue by which such methods might be developed is suggested based on the stretched spiral vortex as a baseline topology. This would result in a nonequilibrium model for turbulence that has greater potential to capture the dynamics in which we are interested. Although these ideas are raised in the context of a future fluvial fluid mechanics, they are applicable to any situation where turbulent flows are forced in complicated ways.

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Coherent structures in flow over hydraulic engineering surfaces

Cited by 121 publications

References 97 publications

Very-large-scale motions in rough-bed open-channel flow

Very-large-scale motions in rough-bed open-channel flow

Turbulence study in the vicinity of piano key weir: relevance, instrumentation, parameters and methods

Flow resistance in natural, turbulent channel flows: The need for a fluvial fluid mechanics

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