Modeling Wall-Induced Forces on Bubbles for Inclined Walls

Moraga, Francisco; Cancelos, Silvina; Lahey, R.T.

doi:10.1615/multscientechn.v18.i2.10

Cited by 3 publications

(8 citation statements)

References 13 publications

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“…Moraga et al [5] have developed a model for inclined walls and deformable bubbles, but the model fails to account explicitly for the parameters of the flow such as the Reynolds number or the Weber number. Following an approach similar to Klaseboer et al [6], Moraga et al [7] have used lubrication theory to build an approximation for the force exerted by the wall on the bubble over a range of Reynolds numbers. The idea is to represent the effect of the wall via a pressure force corresponding to the drainage of the film between the bubble and the wall.…”

Section: Imece2006-15049mentioning

confidence: 99%

“…By integration of the equations the time evolution of the wall force can be determined. Moraga et al [7] then derived a simple, parameterbased model for the wall force which could in turn be integrated into more complex simulations for bubbly flows. In its present formulation, the model has only been derived in the axisymmetrical case (one dimension).…”

Section: Imece2006-15049mentioning

confidence: 99%

“…In the above equations, g is the gravity, C d is the drag coefficient for the bubble in the absence of the wall, C vm is the bubble added mass coefficient. Note that following Moraga et al [7], we have not included the history force in the equations, as it is difficult to model accurately and Klaseboer et al [6] have found that it did not seem to have a strong influence on the bubble dynamics.…”

Section: Fig 1: Physical Configurationmentioning

confidence: 99%

“…The reader is referred to Moraga's paper [7] for a general presentation. The main difference of this work with that of Moraga et al [7] is that we solve a two dimensional version of the lubrication and bubble trajectory equation as needed due to the fact that the inclined wall breaks the axial symmetry of the horizontal wall case. The equations constituting (S) are discretized using second-order finite differences and linearized about the current solution.…”

Section: -Numerical Implementa-tionmentioning

confidence: 99%

“…NAG Fortran routine were used to solve for the band-diagonal system within a tolerance of 10 -8 .The code was tested for different spatial resolutions. We used the same time step as Moraga et al [7]. An increase of 30% in the spatial resolution did not produce any noticeable changes.…”

Section: -Numerical Implementa-tionmentioning

confidence: 99%

See 4 more Smart Citations

Numerical Simulation of a Small Bubble Impinging Onto an Inclined Wall

2006

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This paper presents a numerical modeling of the collision between a small bubble -of a few hundred microns, initially moving at terminal velocity, and an inclined wall, with relevance to drag reduction schemes. The theoretical model uses the lubrication theory to describe the film drainage as the bubble approaches the wall, and compute the force exerted by the wall as the integral of the excess pressure due to the bubble deformation. The model is solved using finite differences. The trajectory of the bubble is then determined using equations of classical mechanics. This study is an extension of previous work by Moraga, Cancelos and Lahey, [Multiphase Science and Technology, 18,(2),2006] where the simulation and comparison with experiments was carried out for a horizontal wall. In the present study where the wall is inclined, the bubble trajectory is no longer onedimensional and axisymmetry around the vertical axis is lost, allowing for more complex behavior. The influence of various parameters (Reynolds number, Weber number) is examined. Numerical results are compared with the experimental data from Tsao and Koch [Physics Fluids 9, 44, 1997]

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Section: Imece2006-15049mentioning

confidence: 99%

Section: Imece2006-15049mentioning

confidence: 99%

Section: Fig 1: Physical Configurationmentioning

confidence: 99%

Section: -Numerical Implementa-tionmentioning

confidence: 99%

Section: -Numerical Implementa-tionmentioning

confidence: 99%

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Numerical Simulation of a Small Bubble Impinging Onto an Inclined Wall

2006

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Experiments of air bubbles impacting a rigid wall in tap water

2015

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Trajectory and impact dynamics of bubbles in tap water were studied. Results confirm that bubbles with identical radii can be classified in two categories: fast bubbles and slow bubbles. Each category of bubble can describe zig-zag or helical motion. The aspect ratio and terminal velocity of a bubble depend on its radius and category. Restitution relations are also presented for the two categories of bubble after impact with an horizontal wall. With these relations, the state of a bubble after rebound can be predicted from its state before rebound. The aspect ratio before rebound of the bubble is found to play a key role in the dynamics of the impacts.

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Interaction between the oil droplet in water and wetted wall: Force model and motion law

Lü

Rong

et al. 2023

Physics of Fluids

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To investigate the force model and motion law of oil droplets in water near the wetted wall, oil droplets with R1=0.29mm～0.62mm and oil films with R2 = 1mm～6 mm were solved numerically. In addition to buoyancy, flow resistance and added mass force, film induced force triggered by the wetted wall constraint was also introduced into the force model. The drainage process is described using the Stokes-Reynolds equation and the Young-Laplace equation is used to calculate the pressure within the water film. The results show that the force model can be coupled with the SRYL equation to better describe the drainage dynamics near the wetted wall. The pressure distribution law is closely related to the shape of the water film, especially when the oil-water interface is in the shape of a dimple, which can lead to the formation of negative pressure zones within the water film. The maximum pressure first grows in an exponential, then logarithmic pattern and eventually approaches the equivalent Laplace pressure. Around the critical size, the direction of the film induced force changes and the form of action switches between driving and drag forces. The dominant effect of the film induced force is strongest when the curvature radius of the oil film is comparable to the droplet size.

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Modeling Wall-Induced Forces on Bubbles for Inclined Walls

Cited by 3 publications

References 13 publications

Numerical Simulation of a Small Bubble Impinging Onto an Inclined Wall

Numerical Simulation of a Small Bubble Impinging Onto an Inclined Wall

Experiments of air bubbles impacting a rigid wall in tap water

Interaction between the oil droplet in water and wetted wall: Force model and motion law

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