Article
Mechanics
Vaisakh Sasidharan, Subrahmanyam Duvvuri
Summary: This study investigates the phenomena of self-sustained shock-wave oscillations over conical bodies in a hypersonic wind tunnel at Mach number M = 6, identifying two distinct states of shock-wave oscillations in the flow. The physical mechanisms proposed explain the transitions of the shock-wave system from steady to oscillatory states. The two-parameter nature of the problem introduces unique elements to the flow dynamics compared to the canonical single-parameter problem reported in literature.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
G-Y Yuan, B-Y Ni, Q-G Wu, Y-Z Xue, D-F Han
Summary: Ice breaking is a major challenge in ice-covered water regions, and new methods are constantly being explored. Through experiments, it has been found that high-speed water jets can effectively break ice, potentially serving as a new auxiliary ice-breaking method in the future.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Astronomy & Astrophysics
Thibaud Richard, Pierre Lesaffre, Edith Falgarone, Andrew Lehmann
Summary: This study systematically investigates the physical nature of intense dissipation regions in decaying isothermal magnetohydrodynamical turbulence. The results reveal that these regions mainly correspond to sheets and can be categorized as fast and slow shocks or Alfven discontinuities. The study also finds that the initial conditions and the magnetic Prandtl number have different impacts on the distributions and heating rates within these structures. Additionally, the study shows a strong correlation between the entrance characteristics of the structures.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Mechanics
Vinoth Paramanantham, Sushmitha Janakiram, Rajesh Gopalapillai
Summary: This article investigates the flow structures of a supersonic nozzle operating at off-design conditions, focusing on shock reflections inside the jet and the transition from regular reflection to Mach reflection. It estimates the size of the Mach stem in an inviscid jet and compares the analytical results with computational and experimental results. The study also calculates the growth rates of the Mach stem during the transition and compares them with those in wedge flows.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Wen-Tao Liu, A-Man Zhang, Xu-Hong Miao, Fu-Ren Ming, Yun-Long Liu
Summary: A novel fluid-structure interaction (FSI) scheme based on the immersed boundary method is proposed to study high-speed water entry of slender bodies. The FSI scheme effectively suppresses non-physical force oscillation and describes rigid body motion using a quaternion-based six degrees of freedom motion system. The accuracy and robustness of the FSI scheme are validated using analytical solutions, experimental data, and literature data. The hydrodynamic loads and motion trajectory of different nose configurations are extensively discussed, with a focus on the tail slamming phenomenon.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Wangxia Wu, Qingquan Liu, Bing Wang
Summary: The study numerically investigates high-speed droplet impingement on typical curved surfaces to analyze complex wave structures and cavitation. The analysis includes the evolution of confined shock waves, cavities, and pressure distribution on concave, convex, and flat surfaces, showing different impacts on shock wave strength and cavitation behavior.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Pranav Thakare, Vineeth Nair, Krishnendu Sinha
Summary: The linear interaction analysis (LIA) method has limitations in studying the interaction between vorticity waves and shock waves, especially for cases with large vorticity wave amplitudes, high incidence angles, and large shock wave curvatures. However, the weakly nonlinear analysis can accurately predict the nonlinear effects and provide the correct scaling of these effects.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Peter L. Cone, Matthew Satchell, Luca Di Mare, Matthew McGilvray
Summary: Shock tubes are crucial for the aerothermodynamic modeling of atmospheric entry vehicles. This study isolates and confirms the importance of shock deceleration effect through experiments, linking shock speed variation to experimental results using a numerical tool. These findings are important for both past and present research.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Multidisciplinary Sciences
Ziao Wang, Juntao Chang, Wenxin Hou, Daren Yu
Summary: Experimental study on a single-channel supersonic cascade model during throttling process shows three stages of attached flow, separated flow, and oscillatory flow. The research also reveals that pressure changes in separated flow lead to changes in separated shear layer, followed by movement of shock waves.
SCIENTIFIC REPORTS
(2021)
Article
Mathematics, Interdisciplinary Applications
David Codoni, Georgios Moutsanidis, Ming-Chen Hsu, Yuri Bazilevs, Craig Johansen, Artem Korobenko
Summary: A stable finite element framework for high-speed compressible flows is proposed, utilizing the Streamline-Upwind/Petrov-Galerkin formulation and discontinuity-capturing techniques. The accuracy of full- and reduced-energy formulations is assessed, with a specific focus on a DC formulation suited for hypersonic flows. Verification and validation cases across various flow regimes demonstrate the excellent performance of the framework for advanced applications.
COMPUTATIONAL MECHANICS
(2021)
Article
Astronomy & Astrophysics
Miha Cernetic, Volker Springel, Thomas Guillet, Ruediger Pakmor
Summary: This article investigates the application of numerical methods in astrophysical studies, focusing on the Discontinuous Galerkin (DG) methods for high-order convergence and computational efficiency. The authors address the challenge of treating physical discontinuities, such as shocks, by introducing an artificial viscosity field and incorporating physical viscosity and thermal conductivity. They demonstrate the effectiveness and scalability of their approach through experiments and simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Mechanics
Jesse Capecelatro
Summary: This article reviews and discusses the numerical modeling of high-speed disperse two-phase flows relevant to plume-surface interactions (PSI). It provides an overview of existing drag laws and new insights from particle-resolved numerical simulations.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2022)
Article
Mechanics
Manoj Kumar K. Devaraj, Prahallada Jutur, Srisha M. V. Rao, Gopalan Jagadeesh, Ganesh T. K. Anavardham
Summary: This study investigates the unstarted flow features in hypersonic mixed-compression intakes by varying the internal contraction ratio and throttling ratio. Results show that the actual shock position relative to the cowl and an appropriate length scale are key factors in predicting the different modes of oscillatory unstarted flows.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Wangxia Wu, Bing Wang, Qingquan Liu
Summary: A study on high-speed droplet impingement on a constrained wall with embedded cavities is conducted to achieve high energy convergence and peak pressure amplification. The physical evolution mechanisms of the impinging droplet and the embedded cavities are investigated, and a theoretical prediction model for the intensity of each cavity collapse is established.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Nathan E. E. Grube, M. Pino Martin
Summary: Recent direct numerical simulation studies have shown that in highly compressible regime, the amplification of streamwise Reynolds stress in canonical shock-isotropic turbulence interactions (SITIs) is higher than in previous studies. This can be explained by the relatively high Mach number and significant dilatational energy in the incident flow. Loss of amplification is observed as the flow parameters approach the threshold between wrinkled and broken shock regimes due to highly perturbed shock structure. The proposed parametrization based on root-mean-square Mach number fluctuation improves the collapse of shock structure data, suggesting its applicability to general isotropic inflow fields.
JOURNAL OF FLUID MECHANICS
(2023)