Turbulence characteristics in the bottom layer of a shallow tidal channel

Razaz, Mahdi; Kawanisi, Kiyosi

doi:10.1080/14685248.2012.741322

Cited by 4 publications

(14 citation statements)

References 46 publications

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“…Fluid stresses also peaked during both flooding and ebbing tide near the maximum velocity magnitude similar to previous findings (French and Clifford, ; Thompson et al ., ; Biron et al ., ; Pope et al ., ; Verney et al ., ; Pacheco et al ., ; Korotenko et al ., ). However, the maximum fluid stresses and bed shear stresses derived from the TKE and Reynolds method occurred during ebbing tide, and not under the highest velocity that occurred during flooding tide, similar to results of Razaz and Kawanisi () and Rippeth et al . ().…”

Section: Discussionmentioning

confidence: 99%

“…Turbulent kinetic energy production is determined as the product of the Reynolds stress and the velocity shear as (Tennekes and Lumley, ; Rippeth et al ., ; Razaz and Kawanisi, )

P = prefix- ((), (⟨⟩, u' w') \frac{\partial (⟨⟩, u)}{\partial z} + (⟨⟩, v' w') \frac{\partial (⟨⟩, v)}{\partial z})

…”

Section: Bed Shear Stress Turbulent Kinetic Energy and Turbulence DImentioning

confidence: 99%

“…Turbulence in tidal channels is typically generated by bottom shear given the lack of surface injected turbulence that is encountered in the coastal ocean. High levels of turbulence production are found near the bed and decrease strongly upward (Rippeth et al ., ; Wiles et al ., ; Razaz and Kawanisi, ; Korotenko et al ., ). High turbulence production is associated with peak flow conditions, with weaker turbulence close to slack tide (Rippeth et al ., , ; Ralston and Stacey, ; Wiles et al ., ), indicating that turbulence production is proportional to the mean current speed as might be expected.…”

Section: Introductionmentioning

confidence: 99%

“…High turbulence production is associated with peak flow conditions, with weaker turbulence close to slack tide (Rippeth et al ., , ; Ralston and Stacey, ; Wiles et al ., ), indicating that turbulence production is proportional to the mean current speed as might be expected. However, in some cases where the velocities were more rapid during flood flow, Reynolds stress and turbulence production were larger during ebb flow (Razaz and Kawanisi, ), which may be due to flow acceleration (Rippeth et al ., ).…”

Section: Introductionmentioning

confidence: 99%

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Near‐bed shear stress, turbulence production and dissipation in a shallow and narrow tidal channel

Pieterse

Puleo

McKenna

et al. 2015

Earth Surf Processes Landf

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Near-bed, highly resolved velocity profiles were measured in the lower 0.03 m of the water column using acoustic Doppler profiling velocimeters in narrow tidal channels in a salt marsh. The bed shear stress was estimated from the velocity profiles using three methods: the log-law, Reynolds stress, and shear stress derived from the turbulent kinetic energy (TKE). Bed shear stresses were largest during ebbing tide, while near-bed velocities were larger during flooding tide. The Reynolds stress and TKE method gave similar results, while the log-law method resulted in smaller bed shear stress values during ebbing tide. Shear stresses and turbulent kinetic energy followed a similar trend with the largest peaks during ebbing tide. The maximum turbulent kinetic energy was on the order of 1 × 10 À 2 m 2 /s 2 . The fluid shear stress during flooding tide was approximately 30% of the fluid shear stress during ebbing tide. The maximum TKE-derived shear stress was 0.7 N/m 2 and 2.7 N/m 2 during flooding and ebbing tide, respectively, and occurred around 0.02 m above the bed. Turbulence dissipation was estimated using the frequency spectrum and structure function methods. Turbulence dissipation estimates from both methods were maximum near the bed (~0.01 m). Both the structure function and the frequency spectrum methods resulted in maximum dissipation estimates on the order of 4 × 10 À 3 m 2 /s 3 . Turbulence production exceeded turbulence dissipation at every phase of the tide, suggesting that advection and vertical diffusion are not negligible. However, turbulence production and dissipation were within a factor of 2 for 77% of the estimates. The turbulence production and dissipation decreased quickly away from the bed, suggesting that measurements higher in the water column cannot be translated directly to turbulence production and dissipation estimates near the bed.

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Section: Discussionmentioning

confidence: 99%

“…Turbulent kinetic energy production is determined as the product of the Reynolds stress and the velocity shear as (Tennekes and Lumley, ; Rippeth et al ., ; Razaz and Kawanisi, )

P = prefix- ((), (⟨⟩, u' w') \frac{\partial (⟨⟩, u)}{\partial z} + (⟨⟩, v' w') \frac{\partial (⟨⟩, v)}{\partial z})

…”

Section: Bed Shear Stress Turbulent Kinetic Energy and Turbulence DImentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Near‐bed shear stress, turbulence production and dissipation in a shallow and narrow tidal channel

Pieterse

Puleo

McKenna

et al. 2015

Earth Surf Processes Landf

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“…Profiles also did not correlate well neither with the log linear form of logarithmic profile [Kawanisi, 2004;Razaz and Kawanisi, 2012], deduced from the Monin-Obukov similarity, nor with the conventional two-layered flow equations [Mccutcheon, 1981]. Hence, the top flow velocity was .…”

Section: Adcp Field Campaignsmentioning

confidence: 99%

An acoustic travel time method for continuous velocity monitoring in shallow tidal streams

Razaz

Kawanisi

Nistor

et al. 2013

Water Resources Research

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[1] Long-term variations of streamflow in a tidal channel were measured using a Fluvial Acoustic Tomography (FAT) system through one transmission path. FAT is an innovative acoustic technology that utilizes the time-of-travel method to determine velocity between two points from multiple ray paths that traverse the entire cross-section of stream. Due to high spatial variability of flow distribution stationary ADCP measurements were not likely to yield true section-averaged flow velocity and moving-boat ADCP method was therefore used to provide reference data. As such, two short-term moving boat ADCP campaigns were carried out by the authors. In the first campaign, a couple of acoustic stations were added to the FAT system in order to resolve flow angularity in addition to the mean velocity. Comparing the FAT results with corresponding ADCP section-averaged flow direction and velocity indicated remarkable consistency. Second campaign was designed to capture the influence of salt wedge intrusion on the sound propagation pattern. It was found that FAT velocity measurements bias high if acoustic stations lay inside the cooler freshwater layer. Ray-tracing hindcasts suggest that installing acoustic stations inside the salt wedge may significantly improve function of output of the system. Comparing salinities evaluated from long-term FAT travel time records with nodal salinity measurements provided by conductivity-temperature sensors reveals the potential ability of FAT in measuring salt flux.

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Spatiotemporal Response of Currents and Mixing to the Interaction of Tides and River Runoff in a Mesotidal Estuary

et al. 2022

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Turbulence characteristics in the bottom layer of a shallow tidal channel

Cited by 4 publications

References 46 publications

Near‐bed shear stress, turbulence production and dissipation in a shallow and narrow tidal channel

Near‐bed shear stress, turbulence production and dissipation in a shallow and narrow tidal channel

An acoustic travel time method for continuous velocity monitoring in shallow tidal streams

Spatiotemporal Response of Currents and Mixing to the Interaction of Tides and River Runoff in a Mesotidal Estuary

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