Manifold death: A Volume of Fluid implementation of controlled topological changes in thin sheets by the signature method

Chirco, Leonardo; Maarek, Jacob; Popinet, Stéphane; Zaleski, Stéphane

doi:10.1016/j.jcp.2022.111468

Cited by 8 publications

(30 citation statements)

References 33 publications

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“…It is observed that when the MD algorithm is applied, droplets greater than 8Δ sig show grid-converged size statistics; while those smaller than 8Δ sig do not. Apart from the present results and Chirco et al (2022), empirical lower bounds for grid convergence in the form of 8Δ have also been proposed in other works involving two-phase breakup phenomena (see e.g. Rivière et al 2021).…”

Section: Summary Of Numerical Convergence Considerationssupporting

confidence: 60%

“…This suggests that it is the droplet production mechanism through ligament fragmentation which remains somewhat grid dependent, while the droplets resulting from these production events are themselves well resolved. Nevertheless, we highlight that the film fragmentation process is well resolved in our numerical simulations with the aid of the MD algorithm (Chirco et al 2022).…”

Section: Behaviour Of Bag Fragmentsmentioning

confidence: 79%

“…There is also potential need of ensemble averaging when fragments produced from an individual realisation are not sufficient for obtaining statistically meaningful results (Mostert, Popinet & Deike 2022). In particular, as the Navier-Stokes equations do not describe the physical mechanisms that control topological changes at phase boundaries, thin films are subject to uncontrolled numerical perforation when their thickness approaches the minimum grid size (Chirco et al 2022). As a result, the fragment statistics are dependent on grid sizes (Jackiw & Ashgriz 2022), and numerical convergence with respect to bag fragment statistics has not previously been obtained to our knowledge.…”

Section: Introductionmentioning

confidence: 99%

“…Afterwards, Zhang, Chen & Ni (2019) built a topology-based numerical scheme which automatically refines grid cells containing the liquid film bordered by two adjacent bubble interfaces. Finally, Chirco et al (2022) developed an algorithm that randomly perforates thin films once their thickness reduces to a prescribed critical value independent of the grid size. This algorithm is controllable via a set of tuning parameters and has been shown to improve grid convergence behaviour for various two-phase problems including droplet aerobreakup.…”

Section: Introductionmentioning

confidence: 99%

“…We present results of novel multiphase direct numerical simulation of droplet bag breakup using both axisymmetric and fully three-dimensional configurations. We conduct axisymmetric simulations to study pre-breakup deformation dynamics, and three-dimensional studies coupled with the manifold death (MD) algorithm of Chirco et al (2022) to shed light on the breakup dynamics of bag films and acquire statistics of bag film fragments for further analysis of their behaviour, while leaving the validation of the MD algorithm with appropriately tuned parameters for the aerobreakup problem to future work.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Bag film breakup of droplets in uniform airflows

Tang,

Adcock,

Mostert

2023

J. Fluid Mech.

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We present novel numerical simulations investigating the bag breakup of liquid droplets. We first examine the viscous effect on the early-time drop deformation, comparing with theory and experiment. Next, a bag film forms at late time and is susceptible to spurious mesh-induced breakup in numerical simulations, which has prevented previous studies from reaching grid convergence of fragment statistics. We therefore adopt the manifold death (MD) algorithm which artificially perforates thin films once they reach a prescribed critical thickness independent of the grid size, controlled by a numerical parameter $L_{sig}$ . We show grid convergence of fragment statistics when utilising the MD algorithm, and analyse the fragment behaviour and bag film disintegration mechanisms including ligament breakup, node detachment and rim destabilisation. Our choice of the critical thickness parameter $L_{sig}$ is limited by numerical constraints and thus has not been matched to experiment or theory; consequently, the current simulations yield critical bag film perforation thicknesses larger than experimentally observed. The influence of the MD algorithm configuration on the bag breakup phenomena and statistics will be investigated in future work. We also study the effects of moderate liquid Ohnesorge number ( $0.005 \leqslant Oh \leqslant 0.05$ ) on the bag breakup process and fragment statistics, where a non-monotonic dependency of the average diameter of bag film fragments on $Oh$ is found. These results highlight the utility of the MD algorithm in multiphase simulations involving topological changes, and pave the way for physics-based numerical investigations into spume generation at the air–sea interface.

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Section: Summary Of Numerical Convergence Considerationssupporting

confidence: 60%

Section: Behaviour Of Bag Fragmentsmentioning

confidence: 79%