Bulletin of the American Physical Society
77th Annual Meeting of the Division of Fluid Dynamics
Sunday–Tuesday, November 24–26, 2024; Salt Lake City, Utah
Session R31: Supersonics and Hypersonics |
Hide Abstracts |
Chair: Datta Gaitonde, The Ohio State University Room: 255 C |
Monday, November 25, 2024 1:50PM - 2:03PM |
R31.00001: The Effects of Breakup and Evaporation on Droplet impact with Hypersonic Vehicles Prithvi Ramesh, Dorrin Jarrahbashi Hypersonic vehicles cruising through the atmosphere at speeds in excess of Mach 6 can be damaged upon impact with water droplets and solid particles (rain, fog, and hail). The complex and highly transient interaction of droplets with the shock structure and boundary layer surrounding these vehicles has presented a challenge for experimental and computational methods. The main challenge in predicting the potential impact of hydrometeors on the vehicle's surface is the behavior of liquid droplets undergoing simultaneous shock-driven breakup and evaporation, particularly as the droplets interact with the complex flow field around the vehicle. The behavior of the droplets during shock-boundary layer interaction, and boundary layer separation/reattachment, and the oblique/bow shockwaves is investigated considering the flow field around different geometries such as a double wedge and a 3D cone-cylinder flare nose tips at hypersonic speeds. A two-way coupled Euler-Lagrangian model supplemented with Kelvin-Helmholtz Rayleigh-Taylor (KH-RT) hybrid model to capture the effects of droplet breakup is developed. Droplet breakup tends to increase the residence time of droplets residing within the swirling vortices formed due to the boundary layer separation and reattachment and increases the probability of droplet impact on the vehicle's surface. A thorough statistical analysis is conducted to identify the conditions at which droplet impact with the surface is maximized, considering the droplet trajectory and kinetic energy near the surface. |
Monday, November 25, 2024 2:03PM - 2:16PM |
R31.00002: Investigation of high-speed flow past a sphere in open and confined spaces Jihoon Kim, Minki Cho, Jaiyoung Ryu High-speed motion of an object in a confined space induces compressible flow phenomena that are distinctly different from those in an open space. Axisymmetric Reynolds-averaged Navier-Stokes (RANS) equations were solved for the compressible flow past a sphere in both open and confined spaces. The Reynolds numbers considered range from 15,000 to 150,000, based on the sphere diameter. Additionally, the Mach numbers vary from 0.4 to 4, demonstrating various compressible flow phenomena around the sphere. For confined spaces, the considered blockage ratios (BR) were 0.09 and 0.4. A detached shock wave forms ahead of the sphere in open space when an object moves at a Mach number exceeding 1. However, in confined spaces, a compression region is generated below the Kantrowitz limit Mach number. Consequently, the drag coefficient in open and confined spaces exhibits different characteristics. To predict the bow shock wave profile and reflection location at a pipe wall, an analytical model combining theoretical considerations for the shock standoff distance and empirical relations for the wave shape was formulated. The drag coefficient in a low BR becomes identical to that in open space beyond a specific Mach number. In confined spaces, low and high BRs exhibit two distinct trends in drag coefficients. These findings on the new limit and drag coefficient enhance the understanding of compressible flow physics and aerodynamic characteristics at high Mach numbers in confined spaces. |
Monday, November 25, 2024 2:16PM - 2:29PM |
R31.00003: ABSTRACT WITHDRAWN
|
Monday, November 25, 2024 2:29PM - 2:42PM |
R31.00004: Modeling Unsteady Aerodynamic Response Due to Surface Deformation on a Mach 6 Fin Using a Parallel Shear Flow Approach Chinmay Shailendra Upadhye, Daniel J Bodony Aerodynamic loads experienced by control fins on hypersonic vehicles can be modeled with varying levels of fidelity. Control fins that experience surface deformation may experience unsteady loads that are significantly impacted by complex local flow features. This work will study the aerodynamic response by approximating the known viscous base flow around a Mach 6 fin using a parallel shear flow. The Fourier-transformed linearized 2D Euler equations will be solved for a panel located on the fin undergoing a specified deformation in this parallel base flow. This approach will take into consideration the effect of the base flow itself on the governing equations and the flow solution. The results will be compared to piston theory variants that also incorporate viscous base flows, as well as to 2D Navier-Stokes unsteady CFD solutions. The comparison will be made over a range of parameters, including different Reynolds numbers, panel oscillation reduced frequencies, and panel mode shapes. |
Monday, November 25, 2024 2:42PM - 2:55PM |
R31.00005: Compressibility and vibrational-excitation effects in hypersonic shock-turbulence interaction Alberto Cuadra Lara, Christopher T Williams, Mario Di Renzo, Cesar Huete The interaction of turbulence with shock waves significantly modulates the frequency and amplitude of hydrodynamic fluctuations encountered by aerospace vehicles in low-altitude hypersonic flight. In these high-speed flows, intrinsic compressibility effects emerge together with high-enthalpy phenomena in the form of internal-energy excitation. The present study directly compares direct numerical simulation (DNS) and linear interaction analysis (LIA) to characterize the impact of density fluctuations and endothermic processes on Mach-5 canonical shock-turbulence interaction. Whereas the computational effort entails directly resolving all relevant length scales and nonlinear interactions, the LIA framework models the upstream compressible turbulence as a superposition of weakly vortical, entropic, and acoustic fluctuations. Both the numerical and theoretical approaches reveal that increasing upstream compressibility serves to augment the turbulent kinetic energy (TKE) across the shock-turbulence interaction for varying turbulent Mach numbers. The effect of endothermicity is likewise assessed in each framework by introducing equilibrium vibrational excitation, which is shown to further amplify the TKE downstream of the shock. |
Monday, November 25, 2024 2:55PM - 3:08PM |
R31.00006: Intrinsic compressibility effects in near-wall turbulence Asif Manzoor Hasan, Pedro Costa, Johan Larsson, Sergio Pirozzoli, Rene Pecnik The impact of intrinsic compressibility effects --- changes in fluid volume due to pressure variations --- on high-speed wall-bounded turbulence has often been overlooked or incorrectly attributed to mean property variations. To unambiguously quantify these intrinsic compressibility effects, we perform direct numerical simulations of compressible turbulent channel flows with nearly uniform mean properties. Our simulations reveal that intrinsic compressibility effects yield a significant upward shift in the logarithmic mean velocity profile that can be attributed to the reduction in the turbulent shear stress. This reduction stems from the weakening of the near-wall quasi-streamwise vortices. We in turn attribute this weakening to the spontaneous opposition of sweeps and ejections from the near-wall expansions and contractions of the fluid, and provide a theoretical explanation for this mechanism. Our results also demonstrate that intrinsic compressibility effects are responsible for the increase in the inner-scaled streamwise turbulence intensity in compressible flows compared to incompressible flows, previously regarded to be an effect of mean property variations. |
Monday, November 25, 2024 3:08PM - 3:21PM |
R31.00007: Effect of Surface Roughness on Hypersonic Turbulent Boundary Layers Mateus Schuabb, Lian Duan, Datta V Gaitonde Direct numerical simulation (DNS) of a Mach 4.9 turbulent boundary layer negotiating periodic crosshatch (i.e., diamond) roughness is performed to generate physical understanding of hypersonic, rough-wall boundary layers. The freestream conditions and roughness geometries of the DNS match those tested at Texas A&M University (TAMU) and direct comparison with the TAMU experiments is first conducted. Boundary-layer statistics from the DNS are then presented to provide detailed insights into the scaling of turbulence characteristics and their dependence on roughness parameters. Data-driven techniques including dynamic mode decomposition (DMD) and spectral proper orthogonal decomposition (SPOD) are also performed to understand the effect of roughness on coherent structures and their impact on surface thermo-mechanical loading. |
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. |
© 2025 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