Article
Chemistry, Physical
Jianxing Li, Jianfeng Pan, Chao Jiang, Xingyu Shi, Yuejin Zhu, Evans K. Quaye
Summary: The study utilizes the solver DCRFoam to analyze detonation reflection over concave and convex double wedges, finding that different wedge angles and critical angles lead to various reflection processes, with reflection processes over concave wedges being more complex than those over convex wedges.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Computer Science, Interdisciplinary Applications
Adnan Mohammadi, Mohammad Hassan Djavareshkian
Summary: This paper introduces a novel hybrid numerical method, SAUSM, which combines the accuracy of AUSM+ and the stability of AUFS through an adaptive weighting function. The effectiveness of SAUSM is demonstrated through a comprehensive suite of test cases, showing its proficiency in resolving shock patterns and discontinuities without introducing anomalies.
INTERNATIONAL JOURNAL OF MODERN PHYSICS C
(2023)
Article
Mechanics
Dagao Wang, Guilai Han, Meikuan Liu, Zonglin Jiang
Summary: In this study, a numerical investigation was conducted on the oblique and bow shock waves ahead of a rotating elliptic cylinder at Mach 5, considering the dynamic effect of the body's motion. The hysteresis loops of aerodynamic coefficients were analyzed, revealing the sensitivity of the moment to rotation. Different hysteresis forms were observed at positive and negative angles of rotation, leading to various shock interaction types and different peak pressures. The driving mechanisms associated with the subsonic region and the modulating action of the formed virtual Laval flow channel were also discussed.
Article
Mechanics
Arun Kumar Perumal, Ethirajan Rathakrishnan
Summary: The experimental investigation on the acoustic properties of supersonic jets reveals scaling laws for the average shock-cell length and supersonic core length, providing important insights into parameter selection and noise control in supersonic flow.
Article
Engineering, Aerospace
Chenyuan Bai, Miaomiao Wang, Ziniu Wu
Summary: This paper investigates symmetric Mach reflection in steady supersonic flow by treating the problem as an entireplane problem. The study reveals that when the Mach stem height is small, the two sliplines exhibit antisymmetric unsteadiness, while they remain symmetric when the Mach stem height is large. The study also identifies the mechanism by which disturbance propagates upstream between the two sliplines and shows that the interaction between transmitted expansion waves and the sliplines increases the amplitude of unstable modes. This study suggests the existence of a new type of compressible jet that warrants further investigation.
CHINESE JOURNAL OF AERONAUTICS
(2023)
Article
Engineering, Geological
Bo Li, Jiafei Wang, Richeng Liu, Yujing Jiang
Summary: The study investigated the nonlinear flow behavior of fluids through 3D discrete fracture networks, considering the effects of fracture number, surface roughness, and fracture aperture. The results showed that streamlines in DFNs become increasingly tortuous as fracture number and roughness increase, leading to stronger inertial effects and greater curvatures of hydraulic pressure-flow rate relations. Increasing fracture aperture and number provide more paths for fluid flow, increasing both viscous and inertial permeabilities.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2021)
Article
Optics
Ruogu Song, Jialiang Sun, Jinyu Wang, Xinyu Li, Yufei Liu, Wencheng Yue, Yan Cai, Shuxiao Wang, Mingbin Yu
Summary: We propose and experimentally demonstrate a novel compact folded Michelson interferometer (FMI) modulator with high modulation efficiency and small footprint. This modulator, by folding the phase shift arms and using shorter traveling wave electrode (TWE), reduces the propagation loss of the RF signal and exhibits excellent performance including low V p -L, low optical insertion loss, high extinction ratio, and wide bandwidth.
Article
Mechanics
G. Sivaprasad, Gopalapillai Rajesh, T. Jayachandran, Arun Kumar Rajagopal
Summary: This paper investigates the strong shock solutions in a supersonic wedge experimentally, analytically, and numerically. Experiments and computations are conducted on scaled-down models for the two types of shock reflection to be possible. The time-resolved schlieren observation of the flow evolution revealed that the shock formation is a highly dynamic transition of the starting shock from a strong Mach reflection (MR) to a weak regular reflection (RR) via a strong RR reflection over a constant shock wave angle for a wedge angle less than the detachment criterion angle for the shock transition. However, when the wedge angle is greater than the detachment criterion angle, the shock moves over the wedge with the MR structures of diminishing Mach stem height at a constant incident shock wave angle. These intermediate shock reflections are found to be unstable and oscillate at high amplitude and low frequencies to upstream pressure fluctuations. The nature of the intermediate shock reflection during the shock transition over the wedge has also been studied using an unsteady second-order two-dimensional compressible Navier-Stokes solver code with shear stress transport k-epsilon turbulence modeling. The computed flow parameters around the intermediate shock reflections confirmed that these are indeed strong shock reflections believed to be unphysical in steady wedge flows.
Article
Engineering, Aerospace
Yoonpyo Hong, Dawoon Lee, Kwanjung Yee, Soo Hyung Park
Summary: The growing interest in urban air mobility has led to the need for physical analyses of the aerodynamic performance and aeroacoustic characteristics of electric vertical takeoff and landing (eVTOL) rotorcraft. This paper proposes a modified enhanced multidimensional limiting process (eMLP) for vorticity conservation, which improves the resolution and efficiency of predicting the performance and noise of eVTOL rotorcraft.
Article
Engineering, Aerospace
Shu-sheng Chen, Zheng Li, Wu Yuan, Hua-Feng Yu, Chao Yan
Summary: In this study, a high-fidelity low-dissipation scheme LD-Roe2 is proposed for simulating unsteady turbulent separated flow, which can better capture the unsteady separated flow and depict finer smaller-scale vortical structures compared with traditional numerical schemes.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Jianxing Li, Jianfeng Pan, Chao Jiang, Yuejin Zhu, Yi Zhang, Abiodun Oluwaleke Ojo
Summary: Numerical investigations were conducted on the reflection of cellular detonation over wedges with rounded corner and compared with reflections over wedges with straight sharp corner. Different types of reflections and the influence of wedge angles were discussed, indicating that the critical angle for transition varied significantly between concave and straight wedges.
Article
Engineering, Electrical & Electronic
Ming Cheng, Yiling Xu, Wang Shen, M. Salman Asif, Chao Ma, Jun Sun, Zhan Ma
Summary: This paper proposes a dual camera system that converts high-spatial-resolution low-frame-rate and low-spatial-resolution high-frame-rate videos into high spatiotemporal resolution stereoscopic videos by exploiting cross-camera redundancies. The system utilizes a learned information fusion network and disparity-guided flow-based warping to achieve this. Experimental results demonstrate the superiority of the model over existing methods on both synthetic and real data.
IEEE TRANSACTIONS ON BROADCASTING
(2022)
Article
Mathematics, Applied
M. Liu, J. Dong, Z. Li, D. F. Li
Summary: In this article, a low numerical dissipation non-staggered central scheme for Riemann problems in hyperbolic conservation laws and convection-diffusion equations is presented. The scheme reduces numerical dissipation through the introduction of a time-space dependent parameter and restriction functions. TVD analysis is provided to support the scheme's accuracy and stability. Numerical examples demonstrate the scheme's remarkable resolution at shock waves, contact discontinuities, and large gradients.
JOURNAL OF SCIENTIFIC COMPUTING
(2023)
Article
Engineering, Aerospace
Myeonghwan Ahn, Duck-Joo Lee, Mihai Mihaescu
Summary: This study investigates the flow behavior of twin jets systems and identifies different coupling modes and pressure fluctuations characteristics at different nozzle separations. The intensity of pressure fluctuations depends on the observer point location and reference plane, while different flapping modes result in varied pressure fluctuations. Additionally, by analyzing periodic pressure fluctuations along jet shear layers, the periodicity of the flow in the downstream region with respect to the fundamental frequency is revealed.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Thermodynamics
Shahid Mehmood, Asad Rehman, Saqib Zia
Summary: This article introduces the development of a fifth-order multi-resolution finite volume WENO scheme combined with the AUSMV numerical flux for analyzing two-phase flow in pipelines. The proposed numerical technique captures pressure wave peaks, suppresses erroneous oscillations, and resolves discontinuities more efficiently and accurately. Its accuracy is verified by solving various test problems and comparing with other numerical schemes.
ADVANCES IN MECHANICAL ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Jin Bao, Zhaoli Guo
Summary: At the equilibrium state of a two-phase fluid system, the chemical potential is constant and the velocity is zero. However, it is challenging to capture this equilibrium state accurately in numerical simulations, resulting in inconsistent thermodynamic interfacial properties and spurious velocities. Therefore, numerical schemes with well-balanced properties are preferred for simulating two-phase flows.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Brian C. Vermeire
Summary: This study presents a framework for implicit large eddy simulation (ILES) of incompressible flows by combining the entropically damped artificial compressibility (EDAC) method with the flux reconstruction (FR) approach. Experimental results demonstrate that the method is accurate and stable for low-order solutions, while higher-order solutions exhibit significantly higher accuracy and lower divergence error compared to reference direct numerical simulation.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Mijian Li, Rui Wang, Xinyu Guo, Xinyu Liu, Lianzhou Wang
Summary: In this study, the flow mechanisms around wall-mounted structures were investigated using Large Eddy Simulation (LES). The impact of inflow turbulence on the flow physics, dynamic response, and hydrodynamic performance was explored. The results revealed strong interference between velocity fluctuations and the wake past the cylinder, as well as significant convection effects in the far wake region.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Donatella Passiatore, Luca Sciacovelli, Paola Cinnella, Giuseppe Pascazio
Summary: A high-order shock-capturing central finite-difference scheme is evaluated for numerical simulations of hyper-sonic high-enthalpy flows out of thermochemical equilibrium. The scheme utilizes a tenth-order accurate central-difference approximation of inviscid fluxes, along with high-order artificial dissipation and shock-capturing terms. The proposed approach demonstrates accuracy and robustness for a variety of thermochemical non-equilibrium configurations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Philipp Bahavar, Claus Wagner
Summary: Condensation is an important aspect in flow applications, and simulating the gas phase and tracking the deposition rates of condensate droplets can capture the effects of surface droplets on the flow while reducing computational costs.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Andras Szabo, Gyorgy Paal
Summary: This paper introduces an efficient calculation method, the parabolized stability equations (PSE), for solving stability equations. By calculating LU factorization once in each marching step, the time spent on solving linear systems of equations can be significantly reduced. Numerical experiments demonstrate the effectiveness of this method in reducing the solution time for linear equations, and its applicability to similar problems.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
A. Khalifa, M. Breuer
Summary: This study evaluates a recently developed data-driven model for collision-induced agglomerate breakup in high mass loading flows. The model uses artificial neural networks to predict the post-collision behavior of agglomerates, reducing computational costs compared to coupled CFD-DEM simulations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Chunmei Du, Maojun Li
Summary: This paper considers the bilayer shallow water wave equations in one-dimensional space and presents an invariant domain preserving DG method to avoid Kelvin-Helmholtz instability.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jean-Michel Tucny, Mihir Durve, Andrea Montessori, Sauro Succi
Summary: The prediction of non-equilibrium transport phenomena in disordered media is a challenging problem for conventional numerical methods. Physics-informed neural networks (PINNs) show potential for solving this inverse problem. In this study, PINNs were used to successfully predict the velocity field of rarefied gas flow, and AdamW was found to be the best optimizer.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Min Gao, Pascal Mossier, Claus-Dieter Munz
Summary: In recent decades, the arbitrary Lagrangian-Eulerian (ALE) approach has gained popularity in dealing with fluid flows with moving boundaries. This paper presents a novel algorithm that combines the ALE finite volume (FV) and ALE discontinuous Galerkin (DG) methods into a stable and efficient hybrid approach. The main challenge of this mixed ALE FV and ALE DG method is reducing the inconsistency between the two discretizations. The proposed algorithm is implemented into a loosely-coupled fluid-structure interaction (FSI) framework and is demonstrated through various benchmark test cases and complex scenarios.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Dawid Strzelczyk, Maciej Matyka
Summary: In this study, the numerical convergence of the Meshless Lattice Boltzmann Method (MLBM) is investigated through three benchmark tests. The results are compared to the standard Lattice Boltzmann Method (LBM) and the analytical solution of the Navier-Stokes equation. It is found that MLBM outperforms LBM in terms of error value for the same number of nodes discretizing the domain.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Kanishka Bhattacharya, Tapan Jana, Amit Shaw, L. S. Ramachandra, Vishal Mehra
Summary: In this work, an adaptive algorithm is developed to address the issue of tensile instability in Smoothed Particle Hydrodynamics (SPH) by adjusting the shape of the kernel function to satisfy stability conditions. The effectiveness of the algorithm is demonstrated through dispersion analysis and fluid dynamics simulations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Luis Laguarda, Stefan Hickel
Summary: We propose several enhancements to improve the accuracy and performance of the digital filter turbulent inflow generation technique, such as introducing a more realistic correlation function and varying target length scales. Additionally, we suggest generating inflow data in parallel at a prescribed time interval to improve computational performance. Based on the results of large-eddy simulations, these enhancements have shown to be beneficial. Suppressing streamwise velocity fluctuations at the inflow leads to the fastest relaxation of pressure fluctuations. However, this approach increases the adaptation length, which can be shortened by artificially increasing the wall-normal Reynolds stresses.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Constantin Zenz, Michele Buttazzoni, Tobias Florian, Katherine Elizabeth Crespo Armijos, Rodrigo Gomez Vazquez, Gerhard Liedl, Andreas Otto
Summary: A new model for compressible multiphase flows involving sharp interfaces and phase change is presented, with a focus on the treatment of compressibility and phase change in the multiphase fluid flow model. The model's accuracy and suitability are demonstrated through comparisons with experimental observations.
COMPUTERS & FLUIDS
(2024)
Article
Computer Science, Interdisciplinary Applications
Joseph O'Connor, Sylvain Laizet, Andrew Wynn, Wouter Edeling, Peter V. Coveney
Summary: This article aims to apply uncertainty quantification and sensitivity analysis to the direct numerical simulation (DNS) of low Reynolds number wall-bounded turbulent channel flow. By using a highly scalable DNS framework and UQ techniques, the study evaluates the influence of different numerical parameters on the simulation results without explicitly modifying the code. The findings provide guidance for numerical simulations of wall-bounded turbulent flows.
COMPUTERS & FLUIDS
(2024)
