Bulletin of the American Physical Society
70th Annual Meeting of the APS Division of Fluid Dynamics
Volume 62, Number 14
Sunday–Tuesday, November 19–21, 2017; Denver, Colorado
Session A30: Compressible Flow: Shock Wave Dynamics and Shock-Particle InteractionCompressible
|
Hide Abstracts |
Chair: Veronica Eliasson, University of California, San Diego Room: 110 |
Sunday, November 19, 2017 8:00AM - 8:13AM |
A30.00001: Shock propagation and mixing though a stratified gas Fabian Chacon, Mirko Gamba In this work, we investigate the characteristics of a shock wave propagating through a stratified gas. The objective is to understand the formation and evolution of the system of waves that results from the interaction, as well as the induced mixing. This work is motivated by understanding the shock-induced mixing and system of waves that arise by the interaction of a detonation wave with the fuel/air injection system in a rotating detonation engine. In these devices, one of the key limiting factors in achieving stable detonation and pressure gain is associated with the stratification induced by a non-uniform and incomplete mixing process. To investigate some of the fundamental aspects of the rapid distortion induced by a detonation wave on the non-uniform flow, we conduct a combined analytical and experimental analysis on a simplified and reduced problem. Experimentally, we consider a single row of injectors of regular spacing that generate a non-reacting turbulent non-uniform flow and are subject to an incident transverse normal shock. Different gasses and shock strengths are used to generate a range of density and velocity ratios that are comparable to what could be experienced through a detonation. Using Schlieren and PLIF imaging, the evolution of mixture fraction throughout the flowfield is investigated. The presence of instabilities and the formation of a system of reflected waves is observed and investigated. A variable property, 1-D, multi-isentropic method of characteristics model is constructed to theoretically investigate the shock propagation and interaction with the stratified flow. [Preview Abstract] |
Sunday, November 19, 2017 8:13AM - 8:26AM |
A30.00002: Shock wave attenuation by water droplets Veronica Eliasson, Qian Wan, Ralf Deiterding The ongoing research on shock wave attenuation is fueled by the desire to predict and avoid damage caused by shock and blast waves. For example, during an explosion in an underground mine or subway tunnel, the shock front is forced to propagate in the direction of the channel. In this work, numerical simulations using water droplets in a 2D channel are conducted to study shock wave attenuation. Four different droplet configurations (1x1, 2x2, 3x3, and 4x4) are considered, where the total volume of water is kept constant throughout all the cases. Meanwhile, the incident shock Mach number was varied from 1.1 to 1.4 with increments of 0.1. The physical motion of the water droplets, such as the center-of-mass drift and velocity, and the energy exchange between air and water are quantitatively studied. Results for center-of-mass velocity, maximum peak pressure and impulse will be presented for all different cases that were studied. [Preview Abstract] |
Sunday, November 19, 2017 8:26AM - 8:39AM |
A30.00003: Shock wave attenuation by thin films Christina Scafidi, Alexander Ivanov, Tal Shemen, Tugra Gokcay, Thomas Spencer, Hongjoo Jeon, Veronica Eliasson Shock wave attenuation due to the placement of a thin film in the path of a planar shock wave was investigated experimentally using a horizontal shock tube with inner square cross section. A high-speed schlieren visualization together with high-frequency pressure transducers were used to study the particulars of the film breakup process and to measure peak pressure and impulse. The effect of varying film thicknesses and types of film materials (both ductile and brittle) on shock wave attenuation was considered. For the case of a film thickness less than or of the order of magnitude of the shock wave thickness, it was shown that the shock wave attenuation effect is dominated by the film thickness rather than the acoustic impedance. For these film thicknesses, the different types of failure mechanisms for the film (brittle vs ductile) do not affect the strength of the transmitted shock wave. [Preview Abstract] |
Sunday, November 19, 2017 8:39AM - 8:52AM |
A30.00004: Numerical simulation of shock wave propagation in water droplet impact on a rough surface Kei Fujisawa In this work shock wave propagation in water droplet impact on a rough surface is numerically studied. The numerical simulation is carried out utilizing two phase full Eulerian approach based on high resolution finite volume method, which allows for shock wave propagation in multiphase flow. To study the shock wave propagation in water droplet impact on a rough surface, an immersed boundary method is used as wall boundary treatment. The maximum impact pressure is computed as a function of surface roughness, and show that the maximum impact pressure increases with increasing relative roughness. [Preview Abstract] |
Sunday, November 19, 2017 8:52AM - 9:05AM |
A30.00005: Gas and particle motions in a rapidly decompressed flow Blair Johnson, Heather Zunino, Ronald Adrian, Amanda Clarke To understand the behavior of a rapidly decompressed particle bed in response to a shock, an experimental study is performed in a cylindrical (D $=$ 4.1 cm) glass vertical shock tube of a densely packed ($\rho \quad =$ 61{\%}) particle bed. The bed is comprised of spherical glass particles, ranging from D50 $=$ 44-297 $\mu $m between experiments. High-speed pressure sensors are incorporated to capture shock speeds and strengths. High-speed video and particle image velocimetry (PIV) measurements are collected to examine vertical and radial velocities of both the particles and gas to elucidate features of the shock wave and resultant expansion wave in the lateral center of the tube, away from boundaries. In addition to optically analyzing the front velocity of the rising particle bed, interaction between the particle and gas phases are investigated as the flow accelerates and the particle front becomes more dilute. Particle and gas interactions are also considered in exploring mechanisms through which turbulence develops in the flow. This work is supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science and Academic Alliance Program, under Contract No. DE-NA0002378. [Preview Abstract] |
Sunday, November 19, 2017 9:05AM - 9:18AM |
A30.00006: A volume-filtered formulation to capture particle-shock interactions in multiphase compressible flows Gregory Shallcross, Jesse Capecelatro Compressible particle-laden flows are common in engineering systems. Applications include but are not limited to water injection in high-speed jet flows for noise suppression, rocket-plume surface interactions during planetary landing, and explosions during coal mining operations. Numerically, it is challenging to capture these interactions due to the wide range of length and time scales. Additionally, there are many forms of the multiphase compressible flow equations with volume fraction effects, some of which are conflicting in nature. The purpose of this presentation is to develop the capability to accurately capture particle-shock interactions in systems with a large number of particles from dense to dilute regimes. A thorough derivation of the volume filtered equations is presented. The volume filtered equations are then implemented in a high-order, energy-stable Eulerian-Lagrangian framework. We show this framework is capable of decoupling the fluid mesh from the particle size, enabling arbitrary particle size distributions in the presence of shocks. The proposed method is then assessed against particle-laden shock tube data. Quantities of interest include fluid-phase pressure profiles and particle spreading rates. The effect of collisions in 2D and 3D are also evaluated. [Preview Abstract] |
Sunday, November 19, 2017 9:18AM - 9:31AM |
A30.00007: Density Discontinuity Interaction with a Structured Array of Particles Brandon E. Osborne, T.L. Jackson, S. Balachandar Discontinuities in density and temperature, or contact discontinuities, arise in a multitude of situations. Explosive detonation and volcanic eruption may both contain contact discontinuities. A shock and contact form when the diaphragm of a shock tube ruptures. Shock interaction with particles has been studied extensively; however, little is known about the effects a contact has on particle force history and the flow field. To better understand the phenomena occurring in this interaction, a series of inviscid, fully-resolved direct numerical simulations were performed. The simulations consisted of a bed of particles arranged in a simple cubic array and a shock and contact initialized near the first particle. Two initial conditions were used, close and intermediate, to highlight combined and more isolated effects of the shock and contact. Close denotes the shock and contact have a small initial separation, such as when a particle bed is close to the diaphragm of a shock tube when it ruptures. Intermediate denotes there is a larger initial separation between the shock and contact, such as when a particle bed is far from the diaphragm. The focus of this talk is to present the simulation results and highlight various phenomena at play during contact-particle interaction. [Preview Abstract] |
Sunday, November 19, 2017 9:31AM - 9:44AM |
A30.00008: Predictive Capability of the~Compressible MRG Equation for an Explosively Driven Particle with Validation Joshua Garno, Frederick Ouellet, Rahul Koneru, Sivaramakrishnan Balachandar, Bertrand Rollin An analytic model to describe the hydrodynamic forces on an explosively driven particle is not currently available. The Maxey-Riley-Gatignol (MRG) particle force equation generalized for compressible flows is well-studied in shock-tube applications, and captures the evolution of particle force extracted from controlled shock-tube experiments. In these experiments only the shock-particle interaction was examined, and the effects of the contact line were not investigated. In the present work, the predictive capability of this model is considered for the case where a particle is explosively ejected from a rigid barrel into ambient air. Particle trajectory information extracted from simulations is compared with experimental data. This configuration ensures that both the shock and contact produced by the detonation will influence the motion of the particle. The simulations are carried out using a finite volume, Euler-Lagrange code using the JWL equation of state to handle the explosive products. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700