Effect of flow confinement on the hydrodynamics of circular impinging jets: implications for erosion assessment

Ghaneeizad, Seyed Mohammad; Atkinson, Joseph F.; Bennett, Sean J.

doi:10.1007/s10652-014-9354-3

Cited by 31 publications

(40 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…found as well in the literature, for instance in [8,23,37]. Dimensionally, the maximum stress appears to be simply proportional to the square of the centerline velocity u 0 of a free jet with the same injection Reynolds number and at the same distance from the injection nozzle.…”

supporting

confidence: 67%

“…in the free jet region where x > h p . For the more usual case of a turbulent jet flow, h p can vary between 6.3D J and 8.3D J according to the literature [9,24,37] or even less as shown by a recent experimental study using PIV [23]. In the present situation, the jet flow regime remains laminar due to the high viscosity of our RIM liquid.…”

Section: Free Jet: Self-similar Modelmentioning

confidence: 65%

“…Some improvements of the model have already been achieved from both experimental and analytical results for the case of a jet impinging on a wall [8,9,23,26,37], but still without considering the scouring crater development and its subsequent implications for the fluid flow at the soil surface, which rapidly departs from the plane conditions. So far, the extent to which these assumptions are relevant in order to describe properly the actual complex hydrodynamical configuration is still unclear.…”

Section: Introductionmentioning

confidence: 99%

“…The main issue is now to define some relevant characteristic extreme values for the identified hydrodynamical quantities involved in the grain erosion, namely the maximal local superficial velocity U max and the maximal gradient (in absolute value) of the dynamical pressure G max = ∂P ∂r max . For this purpose, it seems appropriate to consider firstly the flow configuration of a circular impinging jet on a flat solid wall, which has motivated many studies over the years including notably the following contributions [8,9,23,37]. Here again, all of these works have focused exclusively on turbulent jets, with jet Reynolds numbers being of at least two orders of magnitude larger than in the present situation.…”

mentioning

confidence: 99%

“…For the case of a turbulent free jet, the different quantitative values for all of the centerline velocity decay rate, the radial expansion, the potential core length and the virtual origin depend more or less heavily on the specific conditions of injection and other boundary conditions [4,23,44]. Note also that there is still no consensus in the literature [8,23,37] neither on the position of the maximum shear stress τ max nor on the exact value of the coefficient of proportionality between τ max and ρu 0 2 , often called coefficient of friction C f [23,24]. A typical value of C f is around 4 × 10 −3 for turbulent flow conditions [8,23,24].…”

mentioning

confidence: 99%

See 4 more Smart Citations

Erosion onset of a cohesionless granular medium by an immersed impinging round jet

Brunier-Coulin¹,

Cuéllar²,

Philippe³

2017

Phys. Rev. Fluids

View full text Add to dashboard Cite

To cite this version: AbstractAmong different devices developed quite recently to quantify the resistance to erosion of a natural soil within the broader context of dyke safety, the most commonly used is probably the Jet Erosion Test (JET) in which a scouring crater is induced by impingement of an immersed water jet. A comprehensive experimental investigation on the jet erosion in the specific situation of a cohesionless granular material is presented here. The tests were performed combining special optical techniques allowing for an accurate measurement of the scouring onset and evolution inside an artificially translucent granular sample. The impinging jet hydrodynamics are also analyzed empirically validating the use of a self-similar theoretical framework for the laminar round jet. The critical conditions at the onset of erosion appear to be best described by a dimensionless Shields number based on the inertial drag force created by the fluid flow on the eroded particles rather than on the pressure gradients around them. To conclude, a tentative empirical model for the maximal flow velocity initiating erosion at the bottom of the scoured crater is put forward and discussed in the light of some preliminary results.

show abstract

supporting

confidence: 67%

Section: Free Jet: Self-similar Modelmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Erosion onset of a cohesionless granular medium by an immersed impinging round jet

Brunier-Coulin¹,

Cuéllar²,

Philippe³

2017

Phys. Rev. Fluids

View full text Add to dashboard Cite

show abstract

Sediment transport through self‐adjusting, bedrock‐walled waterfall plunge pools

Scheingross

Lamb

2016

JGR Earth Surface

View full text Add to dashboard Cite

Many waterfalls have deep plunge pools that are often partially or fully filled with sediment.Sediment fill may control plunge-pool bedrock erosion rates, partially determine habitat availability for aquatic organisms, and affect sediment routing and debris flow initiation. Currently, there exists no mechanistic model to describe sediment transport through waterfall plunge pools. Here we develop an analytical model to predict steady-state plunge-pool depth and sediment-transport capacity by combining existing jet theory with sediment transport mechanics. Our model predicts plunge-pool sediment-transport capacity increases with increasing river discharge, flow velocity, and waterfall drop height and decreases with increasing plunge-pool depth, radius, and grain size. We tested the model using flume experiments under varying waterfall and plunge-pool geometries, flow hydraulics, and sediment size. The model and experiments show that through morphodynamic feedbacks, plunge pools aggrade to reach shallower equilibrium pool depths in response to increases in imposed sediment supply. Our theory for steady-state pool depth matches the experiments with an R 2 value of 0.8, withdiscrepancies likely due to model simplifications of the hydraulics and sediment transport. Analysis of 75 waterfalls suggests that the water depths in natural plunge pools are strongly influenced by upstream sediment supply, and our model provides a mass-conserving framework to predict sediment and water storage in waterfall plunge pools for sediment routing, habitat assessment, and bedrock erosion modeling.

show abstract

A Mechanistic Model of Waterfall Plunge Pool Erosion into Bedrock

Scheingross

Lamb

2017

JGR Earth Surface

View full text Add to dashboard Cite

Landscapes often respond to changes in climate and tectonics through the formation and upstream propagation of knickzones composed of waterfalls. Little work has been done on the mechanics of waterfall erosion, and instead most landscape‐scale models neglect waterfalls or use rules for river erosion, such as stream power, that may not be applicable to waterfalls. Here we develop a physically based model to predict waterfall plunge pool erosion into rock by abrasion from particle impacts and test the model against flume experiments. Both the model and experiments show that evolving plunge pools have initially high vertical erosion rates due to energetic particle impacts, and erosion slows and eventually ceases as pools deepen and deposition protects the pool floor from further erosion. Lateral erosion can continue after deposition on the pool floor, but it occurs at slow rates that become negligible as pools widen. Our work points to the importance of vertical drilling of successive plunge pools to drive upstream knickzone propagation in homogenous rock, rather than the classic mechanism of headwall undercutting. For a series of vertically drilling waterfalls, we find that upstream knickzone propagation is faster under higher combined water and sediment fluxes and for knickzones composed of many waterfalls that are closely spaced. Our model differs significantly from stream‐power‐based erosion rules in that steeper knickzones can retreat faster or more slowly depending on the number and spacing of waterfalls within a knickzone, which has implications for interpreting climatic and tectonic history through analysis of river longitudinal profiles.

show abstract

Effect of flow confinement on the hydrodynamics of circular impinging jets: implications for erosion assessment

Cited by 31 publications

References 41 publications

Erosion onset of a cohesionless granular medium by an immersed impinging round jet

Erosion onset of a cohesionless granular medium by an immersed impinging round jet

Sediment transport through self‐adjusting, bedrock‐walled waterfall plunge pools

A Mechanistic Model of Waterfall Plunge Pool Erosion into Bedrock

Contact Info

Product

Resources

About