Article
Computer Science, Hardware & Architecture
Yongzhen Wang, Xuefeng Yan, Jun'an Zhang
Summary: This paper proposes a novel parallel algorithm to tackle heavy computation and long simulation time issues in compressible flows, utilizing GPU's powerful floating-point computing ability. The algorithm employs third-order upwind and fourth-order central difference schemes, along with a third-order Runge-Kutta method for time stepping, and utilizes direct numerical simulation to improve solution accuracy. Optimization strategies are explored to further enhance efficiency, with a classic two-dimensional example confirming the algorithm's accuracy and feasibility, achieving a significant speedup ratio of 18.03 times compared to CPU platform.
JOURNAL OF SUPERCOMPUTING
(2021)
Article
Mechanics
Aurelien Vadrot, Alexis Giauque, Christophe Corre
Summary: This study investigates the effects of a BZT dense gas on the development of turbulent compressible mixing layers at different convective Mach numbers. Results show significant differences in momentum thickness growth rate and temperature variations between perfect gas and dense gas flows, with dense gas also affecting small scale dynamics. However, BZT effects themselves have a small impact on the mixing layer growth.
JOURNAL OF FLUID MECHANICS
(2021)
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
R. Boukharfane, A. Er-raiy, M. Elkarii, M. Parsani
Summary: This study systematically investigates the turbulent flow of spatially developing and high-speed hydrogen/air mixing layers subject to small skew angle ζ using direct numerical simulation. The analysis reveals that skewing leads to faster growth of the inlet structures, enhancing mixing in the process. Through transport equations of Reynolds stresses, the underlying mechanisms responsible for turbulence modulation are analyzed.
Article
Computer Science, Interdisciplinary Applications
Yuhang Wang, Guiyu Cao, Liang Pan
Summary: In this paper, the application of the high-order gas-kinetic scheme (HGKS) in the direct numerical simulation (DNS) of turbulence is introduced. The use of the graphical processing unit (GPU) and CUDA enables the acceleration of HGKS computation, and the development of a multi-GPU HGKS simulation using the message passing interface (MPI) and CUDA is discussed. The performance advantages of GPU acceleration compared to the parallel central processing unit (CPU) code are demonstrated, and the effects of using single precision floating point arithmetic on accuracy are explored.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Mechanics
Yuping Bai, Peiwen Yan, Yifei Yu, Quanbin Zhao, Daotong Chong, Junjie Yan
Summary: In this study, compressible mixing layers are simulated using direct numerical simulation. The origin of spanwise vortex deformations in turbulence is investigated, and it is found that these deformations are a result of a linear superposition of various disturbance modes. The instability mechanism of the simplified vortices is explored, and it is determined that inviscid inflectional instability is responsible for the formation of spanwise and oblique vortices. The findings suggest that the spanwise vortex deformations are a result of the combined effects of a parametric resonant mechanism and inviscid inflectional instability.
Article
Mathematics, Interdisciplinary Applications
Assel Beketaeva, Altynshash Naimanova, Gulzana Ashirova
Summary: In this study, quasi 2D-direct numerical simulations (DNS) were conducted to investigate the supersonic mixing layer of hydrogen-nitrogen flow with solid particles. The formation and influence of unsteady vortex systems, as well as the effect of convective Mach number and hydrogen and nitrogen mass fractions on particle dispersion were examined. The results showed that particle dispersion behavior was similar for different convective Mach numbers, with particles accumulating around vortex circles and in the gaps between vortices. However, for high convective Mach numbers, the presence of local eddy shock waves complicated particle dispersion due to intersecting with these shock waves.
COMPUTATIONAL PARTICLE MECHANICS
(2023)
Article
Mechanics
Xiaoning Wang, Jianchun Wang, Shiyi Chen
Summary: This study investigates the effects of compressibility on the statistics and coherent structures of a temporally developing mixing layer through numerical simulations. The results show that as the convective Mach number increases, the streamwise dissipation becomes more effective in suppressing turbulent kinetic energy. At low convective Mach numbers, the mixing layer is accompanied by spanwise Kelvin-Helmholtz rollers, while at higher convective Mach numbers, large-scale high- and low-speed structures dominate. The study also reveals a correlation between high-shearing motions on top of low-speed structures and the clustering of small-scale vortical structures.
JOURNAL OF FLUID MECHANICS
(2022)
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
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
Meteorology & Atmospheric Sciences
Michel Stefanello, Ricardo A. S. Frantz, Otavio Acevedo, Gervasio Degrazia, Jorge H. Silvestrini
Summary: The study investigates the generation and amplification mechanisms of large-scale nonturbulent motions under strong stable conditions, focusing on the effects of stable stratification on wind-speed and buoyancy oscillations. Horizontal meandering forms in the near-wall region when the ratio of vertical to horizontal wind-speed variance decreases to small orders of magnitude.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Physics, Fluids & Plasmas
Arash Hamzehloo, David J. Lusher, Sylvain Laizet, Neil D. Sandham
Summary: Counter-flow configurations are known for their high efficiency mixers due to the high turbulence intensities, and this paper introduces a simplified version of the problem suitable for direct numerical simulation. The turbulent flow problem between two walls shows distinct characteristics compared to conventional channel flows, with inflectional mean flow and significantly higher turbulence intensity. The study also reveals the potential use of this configuration to investigate compressibility effects on turbulence when certain conditions are met.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Mechanics
Jonas Buchmeier, Alexander Bussmann, Xiangyu Gao, Ivan Bermejo-Moreno
Summary: This study presents a structure-based numerical analysis on passive scalar mixing in decaying homogeneous isotropic turbulence and shock-turbulence interaction canonical configurations, focusing on the temporal evolution of scalar structures and their interactions. The results show that the initial size of structures influences the mixing process and structure breakup, with larger structures leading to increased surface convolution and higher probability of locally hyperbolic geometries. Additionally, shock-induced deformation of structures enhances mixing processes, particularly for larger structures, leading to an amplification of surface-averaged scalar gradient and alignment between scalar gradient and strain-rate eigendirections.
Article
Mechanics
Tie Wei, Zhaorui Li, Daniel Livescu
Summary: Proper scales for the mean flow and Reynolds shear stress in planar turbulent mixing layers are determined and self-similar equations are derived in this study. The derived equations are found to agree well with experimental data.
Article
Mechanics
Jean-Mathieu Teissier, Wolf-Christian Mueller
Summary: This study investigates the inverse transfer of magnetic helicity in large-scale mechanically driven turbulent flows using direct numerical simulations in the ideal magnetohydrodynamics framework. It is found that compressibility leads to smaller absolute values of magnetic helicity scaling exponents, and strong deviations are visible in compressively driven turbulence even at relatively low Mach numbers.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
M. Cimini, E. Martelli, M. Bernardini
Summary: A calibrated delayed detached eddy simulation of a sub-scale cold-gas dual-bell nozzle flow at high Reynolds number and in sea-level mode was conducted, showing a symmetric and controlled flow separation at the inflection point in the over-expanded flow, resulting in low aerodynamic side loads. Analysis of nozzle wall-pressure signature in the frequency domain, in comparison with experimental data for the same geometry and flow conditions, indicates good agreement in the low mean value of side-loads, confirming the interaction between separation-shock and detached shear layer is dampened by the inflection point.
FLOW TURBULENCE AND COMBUSTION
(2021)
Article
Physics, Fluids & Plasmas
Francesco De Vanna, Michele Cogo, Matteo Bernardini, Francesco Picano, Ernesto Benini
Summary: The study presents a general strategy to unify wall-resolved and wall-modeled large-eddy simulation approaches for turbulent wall-bounded compressible flows. The proposed technique allows for accurate reproduction of outer layer turbulent dynamics and automatic switching between the two LES methods. Numerical simulations demonstrate the potential of the approach for predictive analysis of wall-bounded flows at high Reynolds numbers.
PHYSICAL REVIEW FLUIDS
(2021)
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
Green & Sustainable Science & Technology
Giacomo Della Posta, Stefano Leonardi, Matteo Bernardini
Summary: The study suggests that one-way coupled simulations tend to overestimate power production and structural oscillations in wind turbines. Flapwise blade vibration induces aerodynamic damping in the structural motion, while torsional deformation reduces power without introducing significant dynamical effects.
Article
Mechanics
Michele Cogo, Francesco Salvadore, Francesco Picano, Matteo Bernardini
Summary: The structure of high-speed zero-pressure-gradient turbulent boundary layers was studied using direct numerical simulation of the Navier-Stokes equations up to high Reynolds numbers, revealing the consequences in supersonic and hypersonic conditions. Instantaneous fields showed elongated strips of uniform velocity and temperature with clear associations between different streaks.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Engineering, Aerospace
Fulvio Stella, Matteo Cimini, Burak Duendar, Francesca Rossetti, Daniele Barbagallo, Agostino Neri, Matteo Bernardini
Summary: This study presents a numerical investigation on the behavior of launchers during the free-fall phase, considering the fundamental parameters such as Mach number and incidence angle. The results show that the equilibrium position and stability of the launcher are influenced by these parameters.
JOURNAL OF SPACECRAFT AND ROCKETS
(2022)
Article
Mechanics
Matteo Bernardini, Giacomo Della Posta, Francesco Salvadore, Emanuele Martelli
Summary: The study investigates the impact of an oblique shock wave on a turbulent boundary layer through direct numerical simulation, simulating flow conditions similar to a previous experiment. The low-frequency shock unsteadiness is examined using the Morlet wavelet transform, revealing that the broadband shock movement is the result of sparse events with different temporal scales.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Energy & Fuels
Giacomo Della Posta, Stefano Leonardi, Matteo Bernardini
Summary: As horizontal axis wind turbines grow in size, they are exposed to various sources of unsteadiness. This study uses a 2D unsteady aerodynamics model to improve the description of blades' aerodynamic response and examines the aeroelastic response of a utility-scale wind turbine using fluid-structure interaction (FSI) solver. The results show that the external half of the blade is dominated by aeroelastic effects, while the internal half is influenced by significant unsteady aerodynamics phenomena.
Article
Engineering, Aerospace
Andrea Di Mascio, Emanuele Martelli, Matteo Bernardini, Fulvio Stella, Agostino Neri
Editorial Material
Computer Science, Interdisciplinary Applications
Matteo Bernardini, Davide Modesti, Francesco Salvadore, Srikanth Sathyanarayana, Giacomo Della Posta, Sergio Pirozzoli
Summary: STREAmS-2.0 is an updated version of the flow solver STREAmS, with an object-oriented design that separates the physics equations from the specific back-end, making the code more suitable for future expansions. It supports NVIDIA-GPU and CPU back-ends, and features improvements in data management, new schemes for the discretization of convective fluxes, recycling/rescaling inflow boundary condition, and a model for thermally perfect gases with variable specific heats.
COMPUTER PHYSICS COMMUNICATIONS
(2023)
Article
Engineering, Aerospace
Giacomo Della Posta, Marco Fratini, Francesco Salvadore, Matteo Bernardini
Summary: This study presents direct numerical simulations of a turbulent boundary layer on a microramp to investigate the impact of Mach number on the flow. The study finds that the flow topology changes significantly due to compressibility effects and the typical wake features are not linearly scaled with the geometry dimensions but depend on the incoming flow conditions. Furthermore, the study explores the spectral content in time and space of the wake, with Kelvin-Helmholtz instability dominating along the shear layer. The shedding onset is postponed and exhibits a lower peak frequency that evolves in space for larger Mach numbers.
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)
