30 results found
Denner F, 2018, Wall collision of deformable bubbles in the creeping flow regime, EUROPEAN JOURNAL OF MECHANICS B-FLUIDS, Vol: 70, Pages: 36-45, ISSN: 0997-7546
Denner F, Charogiannis A, Pradas M, et al., 2018, Solitary waves on falling liquid films in the inertia-dominated regime, JOURNAL OF FLUID MECHANICS, Vol: 837, Pages: 491-519, ISSN: 0022-1120
Denner F, Xiao CN, van Wachem BGM, 2018, Pressure-based algorithm for compressible interfacial flows with acoustically-conservative interface discretisation, Journal of Computational Physics, Vol: 367, Pages: 192-234, ISSN: 0021-9991
© 2018 The Author(s) A pressure-based algorithm for the simulation of compressible interfacial flows is presented. The algorithm is based on a fully-coupled finite-volume framework for unstructured meshes with collocated variable arrangement, in which the governing conservation laws are discretised in conservative form and solved in a single linear system of equations for velocity, pressure and specific total enthalpy, with the density evaluated by an equation of state. The bulk phases are distinguished using the Volume-of-Fluid (VOF) method and the motion of the fluid interface is captured by a state-of-the-art compressive VOF method. A new interface discretisation method is proposed, derived from an analogy with a contact discontinuity, that performs local changes to the discrete values of density and total enthalpy based on the assumption of thermodynamic equilibrium, and does not require a Riemann solver. This interface discretisation method yields a consistent definition of the fluid properties in the interface region, including a unique definition of the speed of sound and the Rankine–Hugoniot relations, and conserves the acoustic features of the flow, i.e. compression and expansion waves. A variety of representative test cases of gas–gas and gas–liquid flows, ranging from acoustic waves and shock tubes to shock-interface interactions in one-, two- and three-dimensional domains, is used to demonstrate the capabilities and versatility of the presented algorithm in all Mach number regimes. The propagation, reflection and transmission of acoustic waves, shock waves and rarefaction fans in interfacial flows are predicted accurately, even for difficult cases that feature fluids with shock impedance matching, transonic shock tubes or strong shocks in gas–liquid flows, as well as on unstructured meshes.
Evrard F, Denner F, Van Wachem B, 2018, Surface reconstruction from discrete indicator functions, IEEE Transactions on Visualization and Computer Graphics, ISSN: 1077-2626
CCBY This paper introduces a procedure for the calculation of the vertex positions in Marching-Cubes-like surface reconstruction methods, when the surface to reconstruct is characterised by a discrete indicator function. Linear or higher order methods for the vertex interpolation problem require a smooth input function. Therefore, the interpolation methodology to convert a discontinuous indicator function into a triangulated surface is non-trivial. Analytical formulations for this specific vertex interpolation problem have been derived for the 2D case by Manson et al. [Eurographics (2011) 30, 2] and the straightforward application of their method to a 3D case gives satisfactory visual results. A rigorous extension to 3D, however, requires a least-squares problem to be solved for the discrete values of a symmetric neighbourhood. It thus relies on an extra layer of information, and comes at a significantly higher cost. This paper proposes a novel vertex interpolation method which yields second-order-accurate reconstructed surfaces in the general 3D case, without altering the locality of the method. The associated errors are analysed and comparisons are made with linear vertex interpolation and the analytical formulations of Manson et al. [Eurographics (2011) 30, 2].
© 2018 Cambridge University Press. Experiments over the last 50 years have suggested a tentative correlation between the surface (shear) viscosity and the stability of a foam or emulsion. We examine this link theoretically using small-amplitude capillary waves in the presence of a surfactant solution of dilute concentration, where the associated Marangoni and surface viscosity effects are modelled via the Boussinesq-Scriven formulation. The resulting integro-differential initial value problem is solved analytically, and surface viscosity is found to contribute an overall damping effect to the amplitude of the capillary wave with varying degree depending on the length scale of the system. Numerically, we find that the critical damping wavelength increases for increasing surface concentration but the rate of increase remains different for both the surface viscosity and the Marangoni effect.
Charogiannis A, Denner F, van Wachem BGM, et al., 2017, Detailed hydrodynamic characterization of harmonically excited falling-film flows: A combined experimental and computational study, PHYSICAL REVIEW FLUIDS, Vol: 2, ISSN: 2469-990X
Charogiannis A, Denner F, van Wachem BGM, et al., 2017, Statistical characteristics of falling-film flows: A synergistic approach at the crossroads of direct numerical simulations and experiments, PHYSICAL REVIEW FLUIDS, Vol: 2, ISSN: 2469-990X
Denner F, Evrard F, Serfaty R, et al., 2017, Artificial viscosity model to mitigate numerical artefacts at fluid interfaces with surface tension, COMPUTERS & FLUIDS, Vol: 143, Pages: 59-72, ISSN: 0045-7930
Denner F, Pare G, Zaleski S, 2017, Dispersion and viscous attenuation of capillary waves with finite amplitude, 8th Meeting of the International-Marangoni-Association (IMA), Publisher: SPRINGER HEIDELBERG, Pages: 1229-1238, ISSN: 1951-6355
Evrard F, Denner F, van Wachem B, 2017, Estimation of curvature from volume fractions using parabolic reconstruction on two-dimensional unstructured meshes, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 351, Pages: 271-294, ISSN: 0021-9991
Shen L, Denner F, Morgan N, et al., 2017, Marangoni effect on small-amplitude capillary waves in viscous fluids, PHYSICAL REVIEW E, Vol: 96, ISSN: 2470-0045
Xiao C-N, Denner F, van Wachem BGM, 2017, Fully-coupled pressure-based finite-volume framework for the simulation of fluid flows at all speeds in complex geometries, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 346, Pages: 91-130, ISSN: 0021-9991
Charogiannis A, Pradas M, Denner F, et al., 2016, Hydrodynamic characteristics of harmonically excited thin-film flows: Experiments and computations, 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
Denner F, 2016, Frequency dispersion of small-amplitude capillary waves in viscous fluids, PHYSICAL REVIEW E, Vol: 94, ISSN: 2470-0045
Denner F, Pradas M, Charogiannis A, et al., 2016, Self-similarity of solitary waves on inertia-dominated falling liquid films, PHYSICAL REVIEW E, Vol: 93, ISSN: 2470-0045
Charogiannis A, Markides CN, Denner F, et al., 2015, A simultaneous application of PLIF-PIV-PTV for the detailed experimental study of the hydrodynamic characteristics of thin film flows, 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics (HEFAT2015)
Denner F, van Wachem BGM, 2015, Numerical time-step restrictions as a result of capillary waves, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 285, Pages: 24-40, ISSN: 0021-9991
Denner F, van Wachem BGM, 2015, TVD differencing on three-dimensional unstructured meshes with monotonicity-preserving correction of mesh skewness, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 298, Pages: 466-479, ISSN: 0021-9991
Denner F, Vieweg M, Markides N, et al., 2014, Interfacial heat transfer of liquid film flows in narrow channels, 7th Conference of the International Marangoni Association
Denner F, van Wachem B, 2014, Numerical methods for interfacial flows with high density ratios and high surface tension, 7th Conference of the International Marangoni Association
Denner F, van Wachem BGM, 2014, Fully-Coupled Balanced-Force VOF Framework for Arbitrary Meshes with Least-Squares Curvature Evaluation from Volume Fractions, NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS, Vol: 65, Pages: 218-255, ISSN: 1040-7790
Denner F, van Wachem BGM, 2014, Accurate advection of sharp interfaces on arbitrary meshes
Denner F, van Wachem BGM, 2014, Capillary time-step constraint with implicit and explicit treatment of surface tension
Denner F, van der Heul DR, Oud GT, et al., 2014, Comparative study of mass-conserving interface capturing frameworks for two-phase flows with surface tension, INTERNATIONAL JOURNAL OF MULTIPHASE FLOW, Vol: 61, Pages: 37-47, ISSN: 0301-9322
Denner F, van wachem BGM, 2014, Compressive VOF method with skewness correction to capture sharp interfaces on arbitrary meshes, JOURNAL OF COMPUTATIONAL PHYSICS, Vol: 279, Pages: 127-144, ISSN: 0021-9991
van Wachem BGM, Denner F, 2014, A fully coupled solver approach for multiphase flow problems
Denner F, van Wachem BGM, 2013, Force-balancing at moving surface-tension-dominated interfaces on collocated unstructured meshes, 8th International Conference on Multiphase Flows (ICMF 2013)
Denner F, van Wachem BGM, 2013, On the convolution of fluid properties and surface force for interface capturing methods, INTERNATIONAL JOURNAL OF MULTIPHASE FLOW, Vol: 54, Pages: 61-64, ISSN: 0301-9322
Denner F, van Wachem BGM, 2012, Two-Phase Flow Modelling on Arbitrary Meshes: Superior VOF Curvature Estimation and the Issue of Convolution, International Conference on Numerical Methods in Multiphase Flow
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