Interface tracking

In the following sections a description of the HED used in these studies, a list of their measured properties, and preliminary results of droplet experiments for solutions of solid HED formulations in JP-10 and liquid HED compounds are given. These data are needed to evaluate the combustion characteristics of these new fuels as individual compounds or as additives to existing fuel systems and to provide a basis for the development of the predictive capability of solid-gas interface tracking in a turbulent reacting flow. 

Gueyffier, D., Li, J., Nadim, A., Scardovelli, R., and Zaleski, S. (1999) Volume-of-Fluid Interface Tracking with Smoothed Surface Stress Methods for Three-Dimensional Flows, Journal of Computational Physics, Vol. 152(2), pp. 423-456. 

Rider, W.J. and Kothe, D.B. (1995), Stretching and rearing interface tracking methods, Los Alamos National Laboratory (http //www.c3.lanl.gov/ wjr/pubs.html). 

G. Cerne, S. Petelin, I. Tiselj, Coupling of the interface tracking and the two-fluid models for the simulation of incompressible two-phase flow, Journal of Computational Physics, vol. 171, 776-804, 2001. 

Rider WJ, Kothe DB (1995) Stretching and Tearing Interface Tracking Methods. AIAA paper 95-1717, pp. 806-816. 

In contrast to traditional DNS, the simulation of two phases requires very advanced numerical techniques for handling the deforming free surface. With large density differences, stability can be a problem [9]. Also, interface tracking codes require several hundred percent more central processing unit (CPU) time than single-phase codes, making such simulations expensive. 

There have been only a few major attempts to apply interface tracking to primary atomization [9, 10]. However, both of these codes treated all variables, excepting density, as continuous across the interface, which could have implications for their accuracy. For example, the discontinuity in viscosity causes the first derivative of velocity to change abruptly at an interface. 

Other interface tracking schemes have been applied to single drops but have limitations that currently prevent them from being applied to sprays. Helenbrook has developed a very accurate spectral method, but this code is currently limited to two-dimensional, axisymmetric droplet simulations [11]. Cristini et al. have a three-dimensional multiphase flow code that is bcised on the boundary element method (BEM) [12]. However, the BEM will not predict separated flows or capture vorticity effects. 

In this work, direct interface tracking will be used to simulate the evolution of liquid jets and sheets into drops as shown in Fig. 5.1. The fundamental physics of spray flow without relying on assumptions about instabilities will be addressed. 

Keywords Finite element Finite volume Finite difference Volume of fluid Level set Interface tracking Free surface flows Fixed mesh Boimdary-fitted coordinates Boundary integral Marker and cell Immersed boxmdary Volume tracking Surface tracking Surface capturing Interfacial flow modeling... 

Fig. 17.1 Different interfacial flow solution methodologies (a) interface fitting, (b) interface capturing, and (c) interface tracking [4] (Recopied from [4] with permission)...

Fig. 17.3 Free surface in MAC family of interface tracking schemes. The circles represent surface markers. The interface is moved to a new location (dotted line) by first moving the marker particles and then reconstructing the interface using the new location of the markers...

Diffuse interface model Free-surface flow Front capmring Front tracking Interface tracking Interfacial flow Level set method Phase-field method Volume-of-fluid (VOF) method... 

Broadly speaking, there are two computational approaches to solving fluid flow problems that include an evolving interface between two fluid phases. These can be categorized as interface tracking and interface capturing. The former refers to methods that explicitly parameterize the interface and follow the points on the surface... 

Sun Y, Beckermann C (2007) Sharp interface tracking using the phase-field equation. J Comput Phys 220 626-653... 

Lakehal D, Meier M, Fulgosi M (2002) Interface tracking towards the direct simulation of heat and mass transfer in multiphase flows. Int J Heat Fluid Flow 23 242-257... 

Gueyffiera D, Lie J, Nadim A, Scardovelli R, Zaleski S (1998) Volume-of-fluid interface tracking with smoothed surface stress methods for three-dimensional flows. J Comput Phys 152 423-456... 

Numerical Techniques for Free Surface Flows Interface Capturing and Interface Tracking... 

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