A low-dissipation convection scheme for the stable discretization of turbulent interfacial flow

Abstract

© 2017. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper analyzes a low-dissipation discretization for the resolution of immiscible, incompressible multiphase flow by means of interface-capturing schemes. The discretization is built on a three-dimensional, unstructured finite-volume framework and aims at minimizing the differences in kinetic energy preservation with respect to the continuous governing equations. This property plays a fundamental role in the case of flows presenting significant levels of turbulence. At the same time, the hybrid form of the convective operator proposed in this work incorporates localized low-dispersion characteristics to limit the growth of spurious flow solutions. The low-dissipation discrete framework is presented in detail and, in order to expose the advantages with respect to commonly used methodologies, its conservation properties and accuracy are extensively studied, both theoretically and numerically. Numerical tests are performed by considering a three-dimensional vortex, an exact sinusoidal function, and a spherical drop subjected to surface tension forces in equilibrium and immersed in a swirling velocity field. Finally, the turbulent atomization of a liquid-gas jet is numerically analyzed to further assess the capabilities of the method.Peer ReviewedPostprint (author's final draft

Tetrahedral adaptive mesh refinement for two‐phase flows using conservative level‐set method

“…The numerical algorithms have been implemented in a parallel C++/MPI platform called TermoFluids 52 . Furthermore, the unstructured finite‐volume CLS method has been extensively verified and validated with several results from the literature, including dam‐break, 16 rising bubbles, 16,21,53,54 bubbly flows, 17‐19 droplet collision against a fluid‐fluid interface and droplets bouncing collision, 18 thermocapillary‐driven motion of deformable fluid particles, 13 Taylor bubbles, 55 atomization of a liquid‐gas jet, 56,57 non‐Newtonian two‐phase flow, 58 and mass transfer from bubble swarms 19,20 . Therefore, this research can be considered as a further step in the development of numerical methodologies to solve two‐phase flows on complex geometries, with the aid of a finite‐volume/level‐set method introduced by References 13,16,17,19, and an adaptive tetrahedral‐mesh refinement method proposed in this work.…”

A numerical study of liquid atomization regimes by means of conservative level-set simulations

“…In Schillaci et al [23] the inclusion of adaptive mesh refinement (AMR) into the existing CLS solver was verified and employed to obtain physical insights of a coaxial 2D turbulent jet. Further verifications and validations of the CLS method on fixed meshes and dynamic meshes have been reported in [19,24,25].…”

“…where p is the pressure, ρ is the density, µ is the dynamic viscosity and S σ is a volumetric source taking into account the effect of surface tension. The convective term, ∇ • (ρuu), is discretized by means of the low-dispersion scheme presented by [23], properly designed for unstable and/or turbulent two-phase flows. The surface tension force, S σ is transformed to a volume force by using a continuum surface force (CSF) approach, proposed by Brackbill et al [32],…”

“…The inclusion of adaptive-mesh-refinement strategy was tested in past works, demonstrating its effectiveness in the simulation of break-up or general multiphase phenomena [21,22]. In Schillaci et al [23] the model is used to carry out the complete simulation of a 2D Coaxial jet in a turbulent scenario.…”

“…The proposed framework has already demonstrated its reliability in general multiphase and unstable phenomena in past works[21,22]. Moreover, in Schillaci et al[23] we used the same strategy to carry out the complete simulation of a 2D Coaxial Jet in a turbulent scenario.In Sec. 3, the described model is applied and verified in the context of 3D atomizing flows by simulating the 3D Coaxial Liquid-Air Jets at Re l =600 andRe l 1.0 × 10 4 , respectively.…”