Computational Evaluation of Shock Wave Interaction with a Cylindrical Water Column

Abstract

Computational fluid dynamics was employed to predict the early stages of the aerodynamic breakup of a cylindrical water column, due to the impact of a traveling plane shock wave. The unsteady Reynolds-averaged Navier–Stokes approach was used to simulate the mean turbulent flow in a virtual shock tube device. The compressible flow governing equations were solved by means of a finite volume-based numerical method, where the volume of fluid technique was employed to track the air–water interface on the fixed numerical mesh. The present computational modeling approach for industrial gas dynamics applications was verified by making a comparison with reference experimental and numerical results for the same flow configuration. The engineering analysis of the shock–column interaction was performed in the shear-stripping regime, where an acceptably accurate prediction of the interface deformation was achieved. Both column flattening and sheet shearing at the column equator were correctly reproduced, along with the water body drift.

Computational Evaluation of Shock Wave Interaction with a Liquid Droplet

“…Furthermore, the streamwise acceleration a cm of the droplet CM was obtained by differentiating the discrete velocity data using second-order finite difference approximations, for both the present CFDs and reference numerical solutions [13]. Looking at the time evolution of this variable, which is reported suitably normalized on the left side of Figure 7, the good agreement with reference data in [15] is confirmed.…”

“…The flow governing equations, which are not reported here for brevity, can be found, for instance, in [28]. The numerical simulations were performed by using the industrial solver Ansys Fluent, which has been successfully employed in analogous works [13,19], as well as in previous CFD studies using RANS models by the same research group [29,30].…”

“…From a numerical point of view, since the droplet aerobreakup under the SIE regime is characterized by a broad range of spatial and temporal scales, the accurate capture of the droplet deformation and fragmentation is particularly demanding in terms of computational power. Nevertheless, computational fluid dynamics (CFD) simulations have been effectively conducted to predict the early stages of the breakup process induced by the impact of a traveling SW. Due to the high computational cost of fully three-dimensional (3D) simulations, several numerical studies have dealt with two-dimensional shock/liquid column interactions [10][11][12][13][14]. In order to make them affordable, in the context of preliminary analyses, 3D computations have been most often conducted by neglecting the effects of molecular viscosity, while resolving the Euler equations [15,16].…”

“…The process is considered in the shear-stripping regime, that is, at relatively high Weber and very low Ohnesorge numbers. In this study, a 3D computational model is developed, which represents the natural extension of our previous two-dimensional work [13]. Numerical calculations are conducted by employing one of the CFD solvers that are commonly and successfully used for building virtual wind tunnels in industrial fluid dynamics research, namely, Ansys Fluent [19].…”

Hybrid VOF–Lagrangian CFD Modeling of Droplet Aerobreakup

“…Due to the high computational cost of fully three-dimensional (3D) simulations, several CFD studies have been conducted in two spatial dimensions, by considering that the shear-induced breakup of a cylindrical liquid column [10][11][12]. Twodimensional simulations have been mostly focused on the early stages of the breakup process, without investigating the droplet fragmentation and the subsequent mist development [13,14]. On the other hand, to make them affordable in the context of preliminary analyses, 3D computations have been most often conducted by solving the Euler equations, while neglecting the viscous effects [15,16].…”