Transient stage comparison of Couette flow under step shear stress and step velocity boundary conditions

Chen, Lei; Liu, Gang; Zhang, Guozhong; Tang, Yuannan; Chai, John C.

doi:10.1016/j.icheatmasstransfer.2015.10.011

Cited by 5 publications

(9 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The solution to this PDE is given by Lei et al (2016) Figure 11 shows the comparison of numerical results with the analytical solution at different times. The numerical results match the analytical solution very well and illustrate the ability of the LBM implementation to capture shear-driven flow correctly.…”

Section: Couette Flowmentioning

confidence: 99%

Modeling of Dynamic Rock–Fluid Interaction Using Coupled 3-D Discrete Element and Lattice Boltzmann Methods

Gardner

Sitar

2019

Rock Mech Rock Eng

View full text Add to dashboard Cite

Scour of rock is a challenging and interesting problem that combines rock mechanics and hydraulics of turbulent flow. On a practical level, rock erosion is a critical issue facing many of the world's dams at which excessive scour of the dam foundation or spillway can compromise the stability of the dam resulting in significant remediation costs, if not direct personal property damage or even loss of life. This interaction between the blocky rock mass and water is analyzed by directly modeling the solid and fluid phases-the individual polyhedral blocks are modeled using the discrete element method (DEM) while water is modeled using the lattice Boltzmann method (LBM). The LBM mesh is entirely independent of the DEM discretization, making it possible to refine the LBM mesh such that transient and varied fluid pressures acting on the rock surfaces are directly modeled. This provides the capability to investigate the effect of water pressure inside the fractured rock mass, along potential sliding planes, and can be extended to rock falls and slides into standing bodies of water such as lakes and reservoirs. Results show that the coupled DEM-LBM implementation is able to accurately capture the interaction between polyhedral rock blocks and fluid by analytically solving for the solid volume fraction in the coupling computations using convex optimization and simplex integration; however, further performance improvements are necessary to simulate realistic, field-scale problems. Particularly, adaptive mesh refinement and multigrid methods implemented in a parallel computing environment will be essential for capturing the highly computationally intensive and multiscale nature of rockfluid interaction.

show abstract

Section: Couette Flowmentioning

confidence: 99%

Modeling of Dynamic Rock–Fluid Interaction Using Coupled 3-D Discrete Element and Lattice Boltzmann Methods

Gardner

Sitar

2019

Rock Mech Rock Eng

View full text Add to dashboard Cite

show abstract

“…A dimensionless viscosity ̃ which the same meaning as the relative coefficient of viscosity in literature [17] is defined as…”

Section: Problem Descriptionmentioning

confidence: 99%

“…When a constant shear force is imposed, the wall velocity develops from its initial stationary value to the developed value. Similar with literature [17], in this article, we use the dimensionless viscosity ̃ to quantify the transient period of a Couette flow under different boundary conditions. During the initial transient period, the measured viscosity is different from the actual fluid viscosity.…”

Section: Problem Descriptionmentioning

confidence: 99%

“…The top wall is always stationary which is the same as literature [17] and can also be written as ( = , ) = 0 for > 0 (6)…”

Section: Governing Equation Initial Condition and Boundary Condition At The Stationary Wallmentioning

confidence: 99%

“…Some concluding remarks are given to conclude the article. where the measured shear stress is the actual shear stress at the inner surface of the moving plate which has been defined in literature [17] and the measured shear rate ̇ is calculated by the actual velocity of moving plate and the distance between two parallel plates as…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Asymptotic analyses of the start-up stage of Couette flow subjected to different boundary conditions

Chen

Liu

Zhang

et al. 2017

International Communications in Heat and Mass Transfer

View full text Add to dashboard Cite

In this article, the process for reaching "developed" stage was investigated under both imposed shear stress and specified velocity boundary conditions. Four specific situations are investigated. These are(1) constant shear stress, (2) linearly increasing shear stress from zero shear, (3) constant velocity and (4) linearly increasing velocity from stationary. Analytical solutions of velocity distributions under these four situations were obtained. A dimensionless viscosity, defined as the ratio of the measured viscosity calculated based on the measuring principle of Couette-type viscometer to the true viscosity of fluid was proposed to describe the initial transient period. We define the "developed" stage when the dimensionless viscosity is 1% away from its final value or when it reaches 1.01. By analyzing Stokes' first problem, compact models of the dimensionless viscosity were expressed and exact quantitative relations among the initial values of dimensionless viscosity under these four specific situations were found. Time periods for Couette flow to reach the "developed" stage was calculated. The development time is the shortest under the constant velocity boundary and is the longest under the linearly increasing shear stress boundary.

show abstract

Influence of ramped pressure gradient on transient flow formation in a horizontal porous channel

Jha

Yunus

2021

Heat Trans

View full text Add to dashboard Cite

The transient flow formation in a horizontal porous channel assuming a ramped pressure gradient is presented. The equation governing the flow is modeled into a partial differential equation (PDE) which is solved by employing the Laplace transformation technique to transform the PDE to an ordinary differential equation (ODE). The obtained ODE is solved by employing the method of undetermined coefficients to obtain the velocity profile in the Laplace domain. The Riemann sum approximation technique is then adopted to change the obtained solution from the Laplace domain into the time domain. For accuracy checks, the numerical results of the obtained equation are reckoned with previously published work, and an excellent agreement is found. For a clearer understanding of the impact of various flow parameters entering the solutions obtained, graphical and tabular representations are offered using MATLAB software. We noticed that the velocity is slower with ramped pressure gradient compared to a constant pressure gradient. This is because the motion of the fluid occurs gradually with ramped pressure gradient.

show abstract

Transient stage comparison of Couette flow under step shear stress and step velocity boundary conditions

Cited by 5 publications

References 33 publications

Modeling of Dynamic Rock–Fluid Interaction Using Coupled 3-D Discrete Element and Lattice Boltzmann Methods

Modeling of Dynamic Rock–Fluid Interaction Using Coupled 3-D Discrete Element and Lattice Boltzmann Methods

Asymptotic analyses of the start-up stage of Couette flow subjected to different boundary conditions

Influence of ramped pressure gradient on transient flow formation in a horizontal porous channel

Contact Info

Product

Resources

About