3D modelling of non-uniform and turbulent flow in vertical slot fishways

Fuentes‐Pérez, Juan Francisco; Silva, Ana T.; Tuhtan, Jeffrey A.; García‐Vega, Ana; Carbonell-Baeza, Ruth; Musall, Mark; Kruusmaa, Maarja

doi:10.1016/j.envsoft.2017.09.011

Cited by 60 publications

(60 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, to assess the effects of hydrodynamics on the fish behavior, numerical modelling (the 3D CFD model FLOW-3D ® ) was used in this study to characterize influential hydrodynamic variables, such as velocity magnitude, TKE, and water depths, present in each configuration tested, in order to identify areas of high velocity and turbulence gradients that might have affected the fish movements. Over the last few years, 3D CFD models have proved to be a practical and robust tool to characterize hydrodynamics on several hydraulic structures, being widely used for the assessment of fish passages (e.g., studies on functioning over a wide range of discharges, prediction of suitable conditions for fish), optimization of designs, and evaluation of different retrofitting solutions [52][53][54][58][59][60][61][62][63][64]. However, given that uncertainty in CFD modelling for environmental fluid mechanics in complex flow fields, like the flow field in the vicinity of a macro-scale roughness (e.g., wake region), can arise from a very wide range of sources, care should be taken when performing a numerical model study [65].…”

Section: Discussionmentioning

confidence: 99%

Assessment of Retrofitted Ramped Weirs to Improve Passage of Potamodromous Fish

Amaral

Quaresma

Branco

et al. 2019

Water

View full text Add to dashboard Cite

The addition of substrates to small instream obstacles, like low-head ramped weirs, has been considered a useful management solution to retrofit those structures and enhance fish passage. Substrate dimensions and spatial arrangement, together with discharge, and consequently water depths, appear as important factors for the creation of hydrodynamic conditions that may facilitate the successful passage of fish, though related studies are scarce to support decision-making. This study assessed the influence of discharge (Q) and different retrofitting designs (RD) on the upstream passage performance of a potamodromous cyprinid, the Iberian barbel (Luciobarbus bocagei). Different substrates (small boulders, large boulders, cobbles) and spatial arrangements (aligned, offset) were tested. Numerical modelling was performed to characterize the hydrodynamics. Results indicate that Q and RD influenced the upstream negotiation of ramped weirs. Cobbles randomly distributed along the ramp (Nature design) was the most successful configuration, recording the highest number of upstream passages. Low velocities along the ramp, and low turbulence downstream, were registered in this configuration, indicating that the use of natural substrate may help to increase the permeability of ramped weirs to fish movements. The outcomes from this work can help engineers and biologists to design more appropriate passage structures for low-head instream obstacles.2 of 18 after assessment, could not be removed, have undergone rehabilitation works to include ramps in their designs (e.g., [11,12]). This design reconfiguration enables water to pass over the ramp, not generating a waterfall [5,10], a condition that may afford a more holistic negotiation by fish [5,13]. Nevertheless, fish swimming abilities, which are closely related to fish guilds and body size [14][15][16][17], and hydrodynamic conditions, such as water depth, discharge, and turbulence present over the ramp and in the vicinity of the structure [5,[18][19][20], are key factors that influence the permeability of such structures to fish movements.The addition of substrates to instream obstacles and fish transposition devices, commonly referred to as retrofitting, has been considered a useful management solution to enhance upstream fish passage [5,[21][22][23][24][25][26][27][28]. The placement of substrates in culverts to mimic natural stream conditions and facilitate fish passage has been successfully implemented since the early 1970s [29]. In low-head ramped weirs, natural substrates like pebbles, cobbles, or boulders, are frequently used as retrofitting solutions to increase the bed roughness, and consequently promote energy dissipation, creating localized zones of low-velocity and turbulence [23][24][25]30] that may be used by fish as resting areas during the upstream negotiation of ramps [20,27,[31][32][33]. These low velocities may be especially important to species of weaker swimming capabilities, such as potamodromous cyprinids [5,21,22]. Substrate dimensions and spatial arrang...

show abstract

Section: Discussionmentioning

confidence: 99%

Assessment of Retrofitted Ramped Weirs to Improve Passage of Potamodromous Fish

Amaral

Quaresma

Branco

et al. 2019

Water

View full text Add to dashboard Cite

show abstract

“…Therefore, Reynolds Average Navier Stokes (RANS) and Large Eddy Simulation (LES) methods are the most reasonable alternatives. The majority of studies have implemented RANS methods as a numerical technique for the 3D modelling of VSF, because these have shown to be capable of providing a compromise between accuracy and computational cost (Fuentes‐Perez et al, ). Therefore, in this study, a computational fluid dynamic (CFD) RANS model was used.…”

Section: Methodsmentioning

confidence: 99%

Effects of bed slope on the flow field of vertical slot fishways

Quaranta

Katopodis²,

Comoglio

2019

River Research & Apps

View full text Add to dashboard Cite

Vertical slot fishways (VSFs) are the most efficient and least selective typology of technical fish passage, due to their ability to remain effective even when significant upstream and/or downstream water level fluctuations occur. Fishway construction costs can be reduced by increasing its bed slope, but this affects the flow field inside the pools, with higher head drops between the basins, as well as turbulence levels and flow velocities, which may affect fish passage. In light of this, a VSF was investigated by 3D numerical simulations to identify the possible effects of the bed slope (using values from 1.67% to 10%) on the flow field and subsequent implications for fish passage. A particular focus was devoted to cyprinind species, but the results can be extended to other species of similar swimming abilities and, therefore, be applicable to multispecies rivers. Flow velocity and turbulence values such as turbulent kinetic energy and Reynolds stresses were analysed from a fish passage perspective in relation to threshold values derived from previous studies. Pool areas where turbulence values are compatible with fish ability and behaviour were quantified. Maps of the location of fish-friendly zones in the VSF pools were produced and can constitute a reference for practical applications in fishway design. The flow field generated with bed slopes lower than 6.67% is more compatible with fish swimming capabilities, because it exhibits a predominantly 2D behaviour and more suitable hydraulic conditions, whereas at higher slopes, turbulence levels in the pools increase.

show abstract

“…The interFOAM solver uses an artificial compression term in the transport equation of α w to define a fluid interface (α w = 0.5) and to avoid the use of interface reconstruction schemes. Detailed information about the VOF method and its implementation in the interFOAM solver can be found in References [26,51,52].…”

Section: Numerical Modellingmentioning

confidence: 99%

“…Due to today's computing power, computational fluid dynamics (CFD) has evolved as a powerful tool for investigating the flow under varying conditions and therefore has a high potential for fishway designs, for both up-and downstream migration. Various researchers applied CFD to investigate upstream fish passages, for example to assess the hydraulic conditions in pool-type fishways [22][23][24][25][26][27] or to optimize the attraction flow of fishway entrances [28,29]. However, downstream migration numerical simulations have been rarely used.…”

mentioning

confidence: 99%

Conceptual Approach for Positioning of Fish Guidance Structures Using CFD and Expert Knowledge

et al. 2019

View full text Add to dashboard Cite

The longitudinal connectivity of many rivers is interrupted by man-made barriers preventing the up- and downstream migration of fishes. For example, dams, weirs, and hydropower plants (HPP) are insuperable obstructions for upstream migration if no special measures like fish passes are put into effect. While upstream fishways have been implemented successfully and are still being optimized, the focus of current research is more and more on effective fish protection and guiding devices for downstream migration. According to current knowledge fish guidance structures (FGS) have a high potential in supporting the downstream migration by leading fishes to a bypass as an alternative to turbine passage. This work presents a structured and straightforward approach for the evaluation of potential locations of FGS combining traditional dimensioning principles with computational fluid dynamics (CFD) and novel findings from etho-hydraulic research. The approach is based on three key aspects: fish fauna, structural conditions, and hydraulic conditions, and includes three assessment criteria, which are used in an iterative process to define potential FGS locations. The hydraulic conditions can be investigated by means of hydrodynamic 3D simulations and evaluated at cross sections of potential FGS positions. Considering fundamentals of fish biology and ethology allows for rating of the flow conditions and thus for a suitability assessment of various locations. The advantage of the proposed procedure is the possibility to assess FGS configurations without implementing the FGS in the numerical model, thus limiting the computational expense. Furthermore, the implementation of various operation conditions is straightforward. The conceptual approach is illustrated and discussed by means of a case study.

show abstract

3D modelling of non-uniform and turbulent flow in vertical slot fishways

Cited by 60 publications

References 60 publications

Assessment of Retrofitted Ramped Weirs to Improve Passage of Potamodromous Fish

Assessment of Retrofitted Ramped Weirs to Improve Passage of Potamodromous Fish

Effects of bed slope on the flow field of vertical slot fishways

Conceptual Approach for Positioning of Fish Guidance Structures Using CFD and Expert Knowledge

Contact Info

Product

Resources

About