Evolution of an eroding cylinder in single and lattice arrangements

Abstract

The coupled evolution of an eroding cylinder immersed in a fluid within the subcritical Reynolds range is explored with scale resolving simulations. Erosion of the cylinder is driven by fluid shear stress. Kármán vortex shedding features in the wake and these oscillations occur on a significantly smaller time scale compared to the slowly eroding cylinder boundary. Temporal and spatial averaging across the cylinder span allows mean wall statistics such as wall shear to be evaluated; with geometry evolving in 2-D and the flow field simulated in 3-D. The cylinder develops into a rounded triangular body with uniform wall shear stress which is in agreement with existing theory and experiments. We introduce a node shuffle algorithm to reposition nodes around the cylinder boundary with a uniform distribution such that the mesh quality is preserved under high boundary deformation. A cylinder is then modelled within an infinite array of other cylinders by simulating a repeating unit cell and their profile evolution is studied. A similar terminal form is discovered for large cylinder spacings with consistent flow conditions and an intermediate profile was found with a closely packed lattice before reaching the common terminal form.

Modelling ripple morphodynamics driven by colloidal deposition

“…The linearly elastic solid model (Section 2.4) used for smoothing the interior mesh nodes is effective at maintaining mesh quality for large domain volume changes; we have previously employed this model for tracking a melting ice front [31] where the domain size increased by an order of a magnitude. We have also used a similar smoothing mesh method, based on a diffusion model, for simulating the evolution of an eroding cylinder in cross flow [30]; where the eroding cylinder shrunk by an order of magnitude during the simulation.…”

“…The boundaries are prescribed with user-defined functions and the mesh interior is dynamically updated at each time step. This model has been validated against experiments with a heart valve [29], with the erosion of a cylinder in cross flow [30] and the melting ice front around a heated cylinder [31]. In this paper, we use the dynamic mesh model, coupled with modelling the silica particle phase, to explore the impact of boundary evolution on accumulation of colloidal silica in pipe flow at the microscale and compare our results with an experimental test rig [32,33].…”

Viscous transport in eroding porous media

“…This coupling between geometry and flow occurs, for example, in applications involving melting (Beckermann & Viskanta 1988;Rycroft & Bazant 2016;Jambon-Puillet, Shahidzadeh & Bonn 2018;Favier, Purseed & Duchemin 2019;Morrow et al 2019), dissolution (Kang et al 2002;Huang, Moore & Ristroph 2015;Moore 2017;Wykes, Huang & Ristroph 2018), deposition (Johnson & Elimelech 1995;Hewett & Sellier 2018), biofilm growth (Tang, Valocchi & Werth 2015) and crack formation (Cho et al 2019). We focus on erosion, a fluid-mechanical process that is prevalent in many geophysical, hydrological and industrial applications (Berhanu et al 2012;Ristroph et al 2012;Hewett & Sellier 2017;Lachaussée et al 2018;López, Stickland & Dempster 2018;Allen 2019;Amin et al 2019).…”

CFD study of fluid flow changes with erosion

“…Erosion by solid particle impingement, however, is just one of the types of erosion investigated and to which the deformation algorithm can be coupled. Another recurrent erosion type, especially in natural processes, is described in [15], [16], [17] and [18]. This type of erosion is a consequence of erodible bodies moving in viscous fluids which results in a purely fluid-mechanical erosion driven by the fluid's shear stress acting on the eroding boundaries.…”