Article
Mechanics
Jie Yao, Fazle Hussain
Summary: Compressible turbulent plane Couette flows with high Reynolds and Mach numbers were studied through direct numerical simulation. Various turbulence statistics were compared with incompressible flows. The skin friction coefficient decreases with Reynolds number but weakly depends on Mach number. The thermodynamic properties show significant variations with Mach number. Proper scaling transformations collapse the mean velocity profiles for compressible and incompressible cases well. Semilocal units yield a better collapse for Reynolds stress profiles compared to wall units. The length scale of near-wall coherent structures and the strength of the superstructures increase with Reynolds number. The streamwise coherence of the superstructures degrades with increasing Mach number.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Jiequan Li, Qinglong Zhang
Summary: In the computation of compressible fluid flows, numerical boundary conditions are necessary for all physical variables at computational boundaries, while only partial physical variables are often prescribed as physical boundary conditions. This paper proposes a one-sided generalized Riemann problem solver that addresses the issue of spurious wave reflections by avoiding the extrapolation technique.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mechanics
Sanmu Chen, HsuChew Lee, Dehao Xu, Minping Wan, Shiyi Chen
Summary: This study implements the twofold integral-based decompositions of skin-friction and wall heat flux coefficients in compressible temporal transitional channel flows to investigate the generation and overshoot of these coefficients during the transition process, as well as the under-prediction of overshoot by constrained large eddy simulation (CLES). The results demonstrate that the mean velocity convection becomes more significant as the Mach number increases in predicting the wall heat flux coefficient, while the Reynolds shear stress and mean velocity gradient with respect to time dominate the transitional process of the skin friction coefficient. The underestimation of overshoots in CLES is primarily attributed to the discrepancies in the variations of mean velocity gradient and mean energy gradient.
Article
Mechanics
Alexis Giauque, Aurelien Vadrot, Paolo Errante, Christophe Corre
Summary: This study analyzes the influence of the physical complexity of real gases on the amplitude of subgrid-scale terms in large eddy simulations, finding that SGS turbulent stress and pressure terms are significant in the momentum equation. Additionally, significant SGS pressure work and fluxes are found in the inertial zone of the turbulent kinetic energy spectrum, highlighting the need for specific models in this area.
Article
Computer Science, Interdisciplinary Applications
C. De Michele, G. Coppola
Summary: In this study, the conservation properties of various discretizations of the compressible Euler equations for shock-free flows were analyzed. The treatment of the energy equation and the induced discrete equations for other thermodynamic quantities were given special focus. The analysis was done both theoretically and numerically, considering the choice of energy equation and the splitting used in the discretization of the convective terms. The performances of different schemes were evaluated using two widely used test cases, and new and potentially useful formulations were also analyzed.
COMPUTERS & FLUIDS
(2023)
Article
Thermodynamics
Shane Nicholas, Mohammad Omidyeganeh, Alfredo Pinelli
Summary: This study uses highly resolved simulations to investigate the physical mechanisms and criteria for the transition regime between filamentous layers in turbulent open channel flows.
FLOW TURBULENCE AND COMBUSTION
(2022)
Article
Mechanics
Jiacheng Chen, Wendong Liang, Lei Han, Yanfei He, Tairan Chen
Summary: The study aims to propose numerical methods for compressible cryogenic cavitating flows and investigate cavitation behaviors and vortex structures. A numerical modeling framework, including large eddy simulations, vapor-liquid equations of state, and a modified mass transport model, is presented. The modified model is validated by simulating liquid nitrogen cavitating flows under inertial and thermal modes, and the influence of thermodynamic effects on compressibility is investigated. The results show that the modified model agrees better with experimental data.
Article
Mechanics
Davide Modesti, Srikanth Sathyanarayana, Francesco Salvadore, Matteo Bernardini
Summary: This study investigates the characteristics of supersonic turbulent channel flow over cubical roughness elements through direct numerical simulation. The results show that the Mach number has a significant impact on the mean velocity profile, while the thermal field is substantially affected by the roughness.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Computer Science, Interdisciplinary Applications
L. Menez, P. Parnaudeau, M. Beringhier, E. Goncalves Da Silva
Summary: In this study, a continuous forcing immersed boundary method and a volume penalization method were used to simulate compressible viscous flows past solid obstacles on a body non-conformal Cartesian grid. The methods were validated on various flow configurations and their accuracy and computational cost were discussed. Furthermore, a new penalization model was designed to improve shock wave reflection and reduce computational cost.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Matteo Bernardini, Davide Modesti, Francesco Salvadore, Sergio Pirozzoli
Summary: STREAmS is a high-fidelity solver for direct numerical simulations of canonical compressible wall-bounded flows. It incorporates state-of-the-art numerical algorithms designed for high-speed turbulent flows, can be used across a wide range of Mach numbers, and shows superior performance with good parallel efficiency, making it ideal for large-scale simulations.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Mechanics
Zhigang Zhang, Fulin Tong, Junyi Duan, Xinliang Li
Summary: This study conducted a direct numerical simulation of an incident shock wave impinging on a 12° supersonic turbulent expansion corner at a 33.2° angle, revealing the significant influence of expansion on the physics of interaction. The expansion led to reduced wall pressure and separation bubble size, affecting the motion induced by the shock. The study also analyzed the evolution of the reattached boundary layer and the generation mechanism of skin friction.
Article
Mathematics, Applied
Changzhen Song, Jianwen Zhang
Summary: This paper investigates an initial and boundary value problem of the Navier-Stokes equations for compressible viscous barotropic flow subject to large external potential forces in a half space Double-struck capital R+3 with Navier's boundary conditions. The global well-posedness of strong solutions with large oscillations and vacuum is established under the condition that the initial energy is suitably small and the unique steady state is strictly away from vacuum. Additionally, the stability of the stationary solution is obtained as a by-product of the study.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Mechanics
Jie Yao, Xi Chen, Fazle Hussain
Summary: Well-resolved direct numerical simulations of turbulent open channel flows were performed, and it was found that the flow behavior in the near-wall region is similar to closed channel flows, but differs notably in the outer region. The free surface in open channel flows plays a crucial role in various flow phenomena.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Amareshwara Sainadh Chamarthi, Natan Hoffmann, Steven Frankel
Summary: In this work, a novel selective discontinuity sensor approach is proposed for numerical simulations of the compressible Navier-Stokes equations. By selectively treating the various waves that the equations comprise, the approach effectively reduces high-frequency oscillations caused by discontinuities. The method can be applied to any method that employs characteristic transformation and shock sensors, and has shown significant improvement in reducing high-frequency oscillations.
Article
Mechanics
Matthew Bross, Sven Scharnowski, Christian J. Kaehler
Summary: Studies have shown that in compressible turbulent boundary layer flows, the frequencies of superstructures have slightly longer streamwise wavelengths, and there is a distinct increase in the spanwise spacing of superstructures in supersonic cases compared to subsonic and transonic turbulent boundary layers.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Niccolo Tonicello, Guido Lodato, Luc Vervisch
Summary: The study discusses a high-order low dissipative numerical framework for modeling unresolved sub-grid scale flow turbulence and capturing shock waves simultaneously. It evaluates the accuracy of the recently developed Spectral Element Dynamic Model by simulating flows around two different airfoil profiles. The results show that the model performs well in detecting spatial under-resolution in high-order flow simulations.
FLOW TURBULENCE AND COMBUSTION
(2022)
Article
Mechanics
Niccolo Tonicello, Guido Lodato, Luc Vervisch
Summary: Direct numerical simulation of a supersonic turbulent boundary layer interacting with a compression/expansion ramp at an angle of 24 degrees shows that compression motions promote forward transfer of kinetic energy, while expansion regions are more likely to experience backscatter of kinetic energy in the presence of compressibility effects. Decomposing the subgrid scale tensor into deviatoric and spherical parts reveals the compressible and incompressible contributions in total kinetic energy transfers across scales. Eddy-viscosity approximation may be a suitable model for the deviatoric part causing forward kinetic energy cascade, while more complex models are needed for the spherical part contributing to backscatter.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Energy & Fuels
Egor Palkin, Mikhail Yu Hrebtov, Darya A. Slastnaya, Rustam Mullyadzhanov, Luc Vervisch, Dmitriy K. Sharaborin, Aleksei S. Lobasov, Vladimir M. Dulin
Summary: Flow dynamics in a model combustion chamber were studied using Large-eddy simulations (LES) and Particle image velocimetry (PIV). The effect of a central jet on the flow dynamics under isothermal and reactive conditions was compared.
Article
Mechanics
Phuc-Danh Nguyen, Huu-Tri Nguyen, Pascale Domingo, Luc Vervisch, Gabriel Mosca, Moncef Gazdallah, Paul Lybaert, Veronique Feldheim
Summary: Thermal radiation is a crucial factor in the design of combustion systems, as it can significantly impact energy efficiency, temperature, and chemical species prediction. Accurate modeling of radiative heat transfer, coupled with finite rate chemistry effects and turbulence, is necessary. Specific expressions for radiative properties of combustion products are required due to the multiple injections of fuels and oxidizers. The simulation and experimental validation of a flameless combustion system demonstrate a fair prediction of heat transfer, energy balance, temperature, and chemical species fields.
Article
Thermodynamics
Luc Vervisch, Guido Lodato, Pascale Domingo
Summary: A novel numerical framework is discussed for simulating the time evolution of non-inertial particle size distributions in flames. The population balance equation is recast in a form that minimizes numerical errors, and a high-order modal decomposition method is introduced for accuracy. Strategies to couple this framework with the simulation of carbon particles dynamics are also discussed.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Pascale Domingo, Luc Vervisch
Summary: This article discusses the specific requirements for simulating turbulent flames using direct numerical simulation (DNS) and reviews the evolution of DNS research in the past five years. It explains how DNS has become a standard tool in numerical turbulent combustion and explores the development of DNS in laboratory burners for turbulent flame modeling. The article also highlights the potential of DNS-generated databases for developing and testing machine learning methods for combustion system control and optimization.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Emilie Yhuel, Guillaume Ribert, Pascale Domingo
Summary: Highly refined simulations of flame/shock interactions (FSI) are performed and analyzed in the context of hydrogen/air combustion in a two-dimensional shock-tube configuration. The study finds that thermal boundary conditions and species transport modeling have a weak impact during the first stages of the FSI, but a significant one once the reflected shock has crossed the flame front.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Computer Science, Interdisciplinary Applications
Z. Nikolaou, L. Vervisch, P. Domingo
Summary: Discrete filters are widely used in digital signal processing and numerical simulations for various purposes. This research focuses on their application in large-eddy simulations and investigates the reconstruction properties and accuracy of different filters. An optimized framework is proposed for calculating filter coefficients, which significantly reduces the computational cost required for reconstruction in deconvolution-based modeling.
COMPUTERS & FLUIDS
(2023)
Article
Thermodynamics
Julian Bissantz, Jeremy Karpowski, Matthias Steinhausen, Yujuan Luo, Federica Ferraro, Arne Scholtissek, Christian Hasse, Luc Vervisch
Summary: In this work, a method is proposed to simulate combustion phenomena using artificial neural networks (ANNs) chemistry manifold. The ANN is trained on a 1D gas combustion database and utilized for 2D flame simulations compared to other models.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Thermodynamics
Huu-Tri Nguyen, Camille Barnaud, Pascale Domingo, Phuc-Danh Nguyen, Luc Vervisch
Summary: Large eddy simulation of a flameless combustion furnace is performed using neural networks to simulate the oxidation of gaseous fuel present in the steel industry. The neural networks are trained by decomposing the thermochemical composition space and returning the increments in time of influential thermochemical quantities. This approach is found to be very efficient in terms of CPU time.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Thermodynamics
Hernan Olguin, Pascale Domingo, Luc Vervisch, Christian Hasse, Arne Scholtissek
Summary: Orthogonal coordinate systems are an attractive alternative for formulating equations for partially premixed combustion in two-dimensional composition space. Despite their remarkable features, these coordinate systems still face difficulties in defining variables with orthogonal gradients and lack closure models for these gradients. In this study, a Lagrangian interpretation of flamelet derivatives is proposed to solve these problems.
COMBUSTION AND FLAME
(2023)
Article
Computer Science, Interdisciplinary Applications
Tian Liang, Lin Fu
Summary: In this work, a new shock-capturing framework is proposed based on a new candidate stencil arrangement and the combination of infinitely differentiable non-polynomial RBF-based reconstruction in smooth regions with jump-like non-polynomial interpolation for genuine discontinuities. The resulting scheme achieves high order accuracy and resolves genuine discontinuities with sub-cell resolution.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Lukas Lundgren, Murtazo Nazarov
Summary: In this paper, a high-order accurate finite element method for incompressible variable density flow is introduced. The method addresses the issues of saddle point system and stability problem through Schur complement preconditioning and artificial compressibility approaches, and it is validated to have high-order accuracy for smooth problems and accurately resolve discontinuities.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Gabriele Ciaramella, Laurence Halpern, Luca Mechelli
Summary: This paper presents a novel convergence analysis of the optimized Schwarz waveform relaxation method for solving optimal control problems governed by periodic parabolic PDEs. The analysis is based on a Fourier-type technique applied to a semidiscrete-in-time form of the optimality condition, which enables a precise characterization of the convergence factor at the semidiscrete level. The behavior of the optimal transmission condition parameter is also analyzed in detail as the time discretization approaches zero.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jonas A. Actor, Xiaozhe Hu, Andy Huang, Scott A. Roberts, Nathaniel Trask
Summary: This article introduces a scientific machine learning framework that uses a partition of unity architecture to model physics through control volume analysis. The framework can extract reduced models from full field data while preserving the physics. It is applicable to manifolds in arbitrary dimension and has been demonstrated effective in specific problems.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Nozomi Magome, Naoki Morita, Shigeki Kaneko, Naoto Mitsume
Summary: This paper proposes a novel strategy called B-spline based SFEM to fundamentally solve the problems of the conventional SFEM. It uses different basis functions and cubic B-spline basis functions with C-2-continuity to improve the accuracy of numerical integration and avoid matrix singularity. Numerical results show that the proposed method is superior to conventional methods in terms of accuracy and convergence.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Timothy R. Law, Philip T. Barton
Summary: This paper presents a practical cell-centred volume-of-fluid method for simulating compressible solid-fluid problems within a pure Eulerian setting. The method incorporates a mixed-cell update to maintain sharp interfaces, and can be easily extended to include other coupled physics. Various challenging test problems are used to validate the method, and its robustness and application in a multi-physics context are demonstrated.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Xing Ji, Fengxiang Zhao, Wei Shyy, Kun Xu
Summary: This paper presents the development of a third-order compact gas-kinetic scheme for compressible Euler and Navier-Stokes solutions, constructed particularly for an unstructured tetrahedral mesh. The scheme demonstrates robustness in high-speed flow computation and exhibits excellent adaptability to meshes with complex geometrical configurations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Alsadig Ali, Abdullah Al-Mamun, Felipe Pereira, Arunasalam Rahunanthan
Summary: This paper presents a novel Bayesian statistical framework for the characterization of natural subsurface formations, and introduces the concept of multiscale sampling to localize the search in the stochastic space. The results show that the proposed framework performs well in solving inverse problems related to porous media flows.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jacob Rains, Yi Wang, Alec House, Andrew L. Kaminsky, Nathan A. Tison, Vamshi M. Korivi
Summary: This paper presents a novel method called constrained optimized DMD with Control (cOptDMDc), which extends the optimized DMD method to systems with exogenous inputs and can enforce the stability of the resulting reduced order model (ROM). The proposed method optimally places eigenvalues within the stable region, thus mitigating spurious eigenvalue issues. Comparative studies show that cOptDMDc achieves high accuracy and robustness.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Andrea La Spina, Jacob Fish
Summary: This work introduces a hybridizable discontinuous Galerkin formulation for simulating ideal plasmas. The proposed method couples the fluid and electromagnetic subproblems monolithically based on source and employs a fully implicit time integration scheme. The approach also utilizes a projection-based divergence correction method to enforce the Gauss laws in challenging scenarios. Numerical examples demonstrate the high-order accuracy, efficiency, and robustness of the proposed formulation.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Junhong Yue, Peijun Li
Summary: This paper proposes two numerical methods (IP-FEM and BP-FEM) to study the flexural wave scattering problem of an arbitrary-shaped cavity on an infinite thin plate. These methods successfully decompose the fourth-order plate wave equation into the Helmholtz and modified Helmholtz equations with coupled conditions on the cavity boundary, providing an effective solution to this challenging problem.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
William Anderson, Mohammad Farazmand
Summary: We develop fast and scalable methods, called RONS, for computing reduced-order nonlinear solutions. These methods have been proven to be highly effective in tackling challenging problems, but become computationally prohibitive as the number of parameters grows. To address this issue, three separate methods are proposed and their efficacy is demonstrated through examples. The application of RONS to neural networks is also discussed.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Marco Caliari, Fabio Cassini
Summary: In this paper, a second order exponential scheme for stiff evolutionary advection-diffusion-reaction equations is proposed. The scheme is based on a directional splitting approach and uses computation of small sized exponential-like functions and tensor-matrix products for efficient implementation. Numerical examples demonstrate the advantage of the proposed approach over state-of-the-art techniques.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Sebastiano Boscarino, Seung Yeon Cho, Giovanni Russo
Summary: This work proposes a high order conservative semi-Lagrangian method for the inhomogeneous Boltzmann equation of rarefied gas dynamics. The method combines a semi-Lagrangian scheme for the convection term, a fast spectral method for computation of the collision operator, and a high order conservative reconstruction and a weighted optimization technique to preserve conservative quantities. Numerical tests demonstrate the accuracy and efficiency of the proposed method.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Jialei Li, Xiaodong Liu, Qingxiang Shi
Summary: This study shows that the number, centers, scattering strengths, inner and outer diameters of spherical shell-structured sources can be uniquely determined from the far field patterns. A numerical scheme is proposed for reconstructing the spherical shell-structured sources, which includes a migration series method for locating the centers and an iterative method for computing the inner and outer diameters without computing derivatives.
JOURNAL OF COMPUTATIONAL PHYSICS
(2024)
