Hybrid Compressible-Incompressible Numerical Method for Transient Drop-Gas Flows

Wadhwa, Amrita R.; Abraham, John; Magi, Vinicio

doi:10.2514/1.10893

Cited by 10 publications

(3 citation statements)

References 20 publications

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“…Recently, Wadhwa et al 10 numerically simulated transient drop-gas flows by a hybrid compressible-incompressible method in order to study a decelerating liquid droplet. Han et al 11 and Aalburg et al 12 numerically investigated axisymmetric liquid drops that were accelerated impulsively, where the density differences between the drops and the ambient fluid were small.…”

Section: Introductionmentioning

confidence: 99%

Direct numerical study of a liquid droplet impulsively accelerated by gaseous flow

Quan

Schmidt

2006

Physics of Fluids

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A liquid spherical droplet impulsively accelerated by a gaseous flow is simulated in order to investigate the drag force and the deformation. The dynamics of the droplet immersed in a gaseous flow are investigated by solving the incompressible Navier-Stokes equations using a finite volume staggered mesh method coupled with a moving mesh interface tracking scheme. The benefit of the current scheme is that the interface conditions are implemented directly on an explicitly located interface with zero thickness. The droplet shape changes as it is accelerated, and the deformation factor of the droplet is as small as 0.2, so mesh adaptation methods are employed to achieve good mesh quality and to capture the interface curvature. The total drag coefficients are found to be larger than typical steady-state drag coefficients of solid spheres at the same Reynolds numbers. This agrees with the observation of Temkin et al. [ J. Fluid Mech. 96, 133 (1980)] that the unsteady drag of decelerating relative flows was always larger than the steady drag. The large recirculation region behind the deformed droplet may explain this greater drag force. The effects of the viscosity ratio, density ratio, and initial Weber number on the droplet dynamics are also studied. It is found that the initial Weber number and the viscosity ratio have significant effects on the droplet dynamics, while the density ratio does not. A liquid spherical droplet impulsively accelerated by a gaseous flow is simulated in order to investigate the drag force and the deformation. The dynamics of the droplet immersed in a gaseous flow are investigated by solving the incompressible Navier-Stokes equations using a finite volume staggered mesh method coupled with a moving mesh interface tracking scheme. The benefit of the current scheme is that the interface conditions are implemented directly on an explicitly located interface with zero thickness. The droplet shape changes as it is accelerated, and the deformation factor of the droplet is as small as 0.2, so mesh adaptation methods are employed to achieve good mesh quality and to capture the interface curvature. The total drag coefficients are found to be larger than typical steady-state drag coefficients of solid spheres at the same Reynolds numbers. This agrees with the observation of Temkin et al. ͓J. Fluid Mech. 96, 133 ͑1980͔͒ that the unsteady drag of decelerating relative flows was always larger than the steady drag. The large recirculation region behind the deformed droplet may explain this greater drag force. The effects of the viscosity ratio, density ratio, and initial Weber number on the droplet dynamics are also studied. It is found that the initial Weber number and the viscosity ratio have significant effects on the droplet dynamics, while the density ratio does not.

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Section: Introductionmentioning

confidence: 99%

Direct numerical study of a liquid droplet impulsively accelerated by gaseous flow

Quan

Schmidt

2006

Physics of Fluids

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“…A similar method to describe the behaviour of compressible bubbles in an incompressible fluid was subsequently presented by Aanjaneya et al [35]. Wadhwa et al [36] proposed a method for computing incompressible liquid drops in a compressible gas, representing the interface as a matching moving mesh and solving the flow of the incompressible fluid using the artificial compressibility method of Chorin [23]. Others proposed algorithms for compressible-incompressible flows applying the same governing equations in non-conservative form in both fluids [37][38][39] and these algorithms are, in general, only applicable to incompressible and low Mach number flows.…”

Section: Algorithms For Compressible-incompressible Flowsmentioning

confidence: 98%

A unified algorithm for interfacial flows with incompressible and compressible fluids

Denner¹,

Wachem²

2022

Preprint

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The majority of available numerical algorithms for interfacial two-phase flows either treat both fluid phases as incompressible (constant density) or treat both phases as compressible (variable density). This presents a limitation for the prediction of many two-phase flows, such as subsonic fuel injection, as treating both phases as compressible is computationally expensive due to the very stiff pressure-density-temperature coupling of liquids. A framework with the capability of treating one phase compressible and the other phase incompressible, therefore, has a significant potential to improve the computational performance and still capture all important physical mechanisms. We propose a numerical algorithm that can simulate interfacial flows in all Mach number regimes, ranging from M = 0 to M > 1, including interfacial flows in which compressible and incompressible fluids interact, within the same pressure-based framework and conservative finite-volume discretisation. For interfacial flows with only incompressible fluids or with only compressible fluids, the proposed pressure-based algorithm and finite-volume discretisation reduce to numerical frameworks that have already been presented in the literature. Representative test cases are used to validate the proposed algorithm, including mixed compressible-incompressible interfacial flows with acoustic waves, shock waves and rarefaction fans.

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“…Recently, Wadhwa et al [20][21][22] conducted numerical studies of the transient deformation and drag properties of decelerating drops in axisymmetric flows. They showed that the deformation and drag coefficient of drops changed gradually in the decelerating flow, and the Weber number and Ohnesorge number influenced the drag coefficient.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Transient Deformation and Drag Characteristics of a Decelerating Droplet

Liu

et al. 2016

AIAA Journal

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A numerical study of the transient deformation and drag properties of impulsively started decelerating drops in axisymmetric flows is conducted. The incompressible Navier-Stokes equations coupled with the volume of fraction method are solved. The differences in the deformation and drag characteristics between the accelerating and decelerating drops are elucidated. The Weber number We has a significant influence on the drag properties of the round drops; however, the effect of the Ohnesorge number Oh is small. A dynamic droplet drag model is provided based on the computational fluid dynamics results to predict the drag coefficient of a decelerating drop. In addition, the flow of liquid drops past an RAE2822 airfoil is considered, and its drag is evaluated using the drag model.

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Hybrid Compressible-Incompressible Numerical Method for Transient Drop-Gas Flows

Cited by 10 publications

References 20 publications

Direct numerical study of a liquid droplet impulsively accelerated by gaseous flow

Direct numerical study of a liquid droplet impulsively accelerated by gaseous flow

A unified algorithm for interfacial flows with incompressible and compressible fluids

Numerical Study of Transient Deformation and Drag Characteristics of a Decelerating Droplet

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