Article
Mathematics, Applied
Giuseppe Sirianni, Barbara Re, Remi Abgrall, Alberto Guardone
Summary: A set of strategies and numerical techniques for simulating weakly compressible two-phase flows is presented, including a pressure formulation of the full Baer-Nunziato equations and a Momentum Weighted Interpolation formulation to mitigate pressure checkerboarding. The proposed approach is thoroughly tested against analytic and experimental data.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Manuel Colera, Jaime Carpio, Rodolfo Bermejo
Summary: In this work, a novel Lagrange-Galerkin method is presented for solving compressible and inviscid flows. The method utilizes high-order continuous finite elements for spatial discretization, high-order implicit-explicit Runge-Kutta schemes for time discretization, and conserves mass, momentum, and total energy. It also incorporates subgrid stabilization and discontinuity-capturing operators based on Brenner's model for viscous flows. The method has been successfully tested on benchmark problems and demonstrates accurate results for both smooth and discontinuous solutions.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mechanics
Yaqing Yang, Liang Pan, Kun Xu
Summary: This paper presents a high-order gas-kinetic scheme on three-dimensional unstructured meshes for compressible Euler and Navier-Stokes equations, utilizing WENO reconstruction and linear weights for improved accuracy, as well as fourth-order temporal discretization and high-order gas-kinetic schemes for solving unsteady and steady problems.
Article
Computer Science, Interdisciplinary Applications
Vadim Maltsev, Dean Yuan, Karl W. Jenkins, Martin Skote, Panagiotis Tsoutsanis
Summary: In this paper, a family of high-order non-oscillatory hybrid DG-FV schemes is developed for mixed-element unstructured meshes. By switching between a DG method and a FV method based on the CWENOZ scheme, the schemes can maintain the high accuracy of DG in smooth regions and the robustness of FV in regions with strong gradients. The CWENOZ variant used has the same accuracy as the DG variant and simplifies the implementation on unstructured meshes. The investigation of several parameters associated with the switching process is conducted, and the methods are successfully applied to solve the 2D and 3D Euler equations.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Mathematics, Applied
Mirco Ciallella, Elena Gaburro, Marco Lorini, Mario Ricchiuto
Summary: In this paper, a simple yet effective high order polynomial correction method is proposed to enhance the consistency of various boundary conditions for the Euler equations in 2D and 3D simulations. The method is a simplified reformulation of the Shifted Boundary Method (SBM) and utilizes a correction based on the extrapolated value of the in cell polynomial to the true geometry. It does not require the explicit evaluation of high order Taylor series and can be easily implemented into existing finite element and finite volume codes. Several validation tests demonstrate the convergence properties and effective extension to flows with shocks.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Computer Science, Interdisciplinary Applications
Valerie Kulka, Patrick Jenny
Summary: An adaptive conservative time integration scheme (ACTI) is proposed for compressible flow simulations. By using decreasing time steps, conservation and periodic synchronization are guaranteed. Compared to previous methods, this new scheme has significant advantages in dealing with compressible flow, especially in the presence of shock waves. The accuracy and computational speedup of the scheme are demonstrated through 1D and 2D test cases.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Thermodynamics
S. Parameswaran, J. C. Mandal
Summary: A robust finite volume framework is developed for solving incompressible two-phase flow problems on structured meshes, and it is extended to unstructured meshes in this paper. The surface tension effect is also modeled to enhance the applicability to real-life engineering problems. Least square and Green-Gauss integral based methods are used to deal with arbitrary unstructured mesh topology. The proposed method shows improved accuracy compared to the structured mesh formulation, as demonstrated through numerical tests involving various forces.
NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS
(2023)
Article
Computer Science, Interdisciplinary Applications
Yuichi Kuya, Wataru Okumura, Keisuke Sawada
Summary: A kinetic energy and entropy preserving finite-volume scheme on unstructured meshes is proposed for stable compressible flow computations. The scheme maintains the characteristics of kinetic energy and entropy during the discretization process and performs stable computations on various unstructured meshes.
JOURNAL OF COMPUTATIONAL PHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Savinien Pertant, Manuel Bernard, Giovanni Ghigliotti, Guillaume Balarac
Summary: This paper presents a robust and accurate method for numerically simulating moving contact lines on complex boundaries with surface wettability effects. The method is validated on 2D and 3D test cases, demonstrating good mass conservation properties and the ability to handle realistic scenarios such as drop detachment from horizontal fibers using dynamic mesh adaptation.
JOURNAL OF COMPUTATIONAL PHYSICS
(2021)
Article
Mathematics, Applied
Panagiotiis Tsoutsanis, Machavolu Sai Santosh Pavan Kumar, Pericles S. Farmakis
Summary: In this paper, the relaxed, high-order, Multidimensional Optimal Order Detection (MOOD) framework is extended to simulate compressible multicomponent flows on unstructured meshes. The extended MOOD-CWENO numerical framework is successfully applied to solve a series of challenging problems, expanding the application range of the algorithm.
APPLIED MATHEMATICS AND COMPUTATION
(2023)
Article
Engineering, Multidisciplinary
Derek C. Thomas, Luke Engvall, Steven K. Schmidt, Kevin Tew, Michael A. Scott
Summary: U-splines are a novel approach to constructing spline bases for representing smooth objects in CAD and CAE. They differ from existing constructions by accommodating local variation in cell size, polynomial degree, and smoothness simultaneously. The U-spline algorithm introduces a new technique for constructing basis functions using local null space solutions.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Computer Science, Interdisciplinary Applications
Sunder Dasika, Dipak Vaghani, Ratnesh K. Shukla
Summary: This paper presents a novel constrained least-squares technique for fourth-order weighted essentially non-oscillatory (WENO) polynomial reconstruction on general unstructured grids. The technique improves the accuracy and spectral resolution of high-order finite-volume reconstruction operation by segregating the matching conditions of the candidate WENO polynomial and the reconstructed state variable and applying different constraints. The proposed approach provides more accurate pointwise estimates and is computationally efficient.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mathematics, Applied
Michael Pries, Andreas Fiolitakis, Peter Gerlinger
Summary: This paper presents efficient numerical solvers for the computation of combustion instabilities, focusing on low Mach number compressible flows. The splitting schemes are utilized to separate the governing equations into subsystems, and advancements are made to improve accuracy and stability. A new gradient-based approach is also introduced for coupling the splitting scheme with characteristic boundary conditions. The proposed improved numerical scheme is validated through academic test cases and a complex swirl combustor simulation on an unstructured grid.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2024)
Article
Computer Science, Interdisciplinary Applications
Ondrej Meca, Lubomir Riha, Branislav Jansik, Tomas Brzobohaty
Summary: The algorithm efficiently loads and processes unstructured mesh databases in a highly-parallel manner in a distributed memory environment, showing the ability to reconstruct large meshes on thousands of processors even from databases not designed for parallel reading.
ADVANCES IN ENGINEERING SOFTWARE
(2022)
Article
Chemistry, Multidisciplinary
Xiaokun Tian, Chao Yang, Yadong Wu, Zhouqiao He, Yan Hu
Summary: This paper presents a method for visualizing large-scale unsteady flow fields using animation. The proposed method improves data reading efficiency and reduces memory usage by analyzing variable description information and constructing a hash table. The effectiveness of the method is validated through testing on four sets of unstructured unsteady flow field data with different data structures. The method enables real-time user interaction and achieves an average frame rate of less than 100ms for animation visualization on personal computers.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Aerospace
Neda Taymourtash, Daniele Zagaglia, Alex Zanotti, Vincenzo Muscarello, Giuseppe Gibertini, Giuseppe Quaranta
Summary: The paper presents experimental investigation of the aerodynamic interaction between a helicopter model and a ship model with a simplified geometry. The study includes wind tunnel tests to assess flow features and the effect of wind conditions on the landing region over the ship deck. The results provide a comprehensive database for studying rotor-ship aerodynamic interaction and developing an identification algorithm for simulating shipboard operations in a flight simulator environment.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Computer Science, Artificial Intelligence
Andrea Zanoni, Matteo Zago, Rita Paolini, Giuseppe Quaranta, Manuela Galli, Pierangelo Masarati
Summary: By conducting a piloted flight simulator campaign, researchers measured biomechanical performance indicators of a helicopter pilot performing complex tasks, finding an increase in muscle activity with task difficulty and providing useful guidance for improving biomechanical simulations and characterizing pilot performance during specific tasks.
IEEE TRANSACTIONS ON HUMAN-MACHINE SYSTEMS
(2021)
Article
Engineering, Aerospace
Neda Taymourtash, Alex Zanotti, Giuseppe Gibertini, Giuseppe Quaranta
Summary: This paper presents the results of wind tunnel tests on the unsteady aerodynamic loads of a scaled helicopter operating in the airwake of a generic frigate model. The results show an increase in unsteadiness with changing approach direction, with higher amplification rates for unsteady loads in non-headwind tests. Furthermore, the effect of approach velocity on unsteady loads varies.
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Computer Science, Interdisciplinary Applications
Stefano Colombo, Barbara Re
Summary: This work presents a novel interpolation-free mesh adaptation technique for the Euler equations within the arbitrary Lagrangian-Eulerian framework. The proposed approach achieves high order accuracy on unstructured grids through a residual distribution scheme and avoids spurious oscillations by enforcing the geometric conservation law. The method is validated through two-dimensional simulations.
COMPUTERS & FLUIDS
(2022)
Article
Computer Science, Interdisciplinary Applications
Barbara Re, Remi Abgrall
Summary: Within the framework of diffuse interface methods, a pressure-based Baer-Nunziato type model is derived for weakly compressible multiphase flows. The model can handle different equations of state and includes relaxation terms characterized by user-defined finite parameters. The solution strategy involves a semi-implicit finite-volume solver for the hyperbolic part and an ODE integrator for the relaxation processes. The developed simulation tool is validated through various tests, showing good agreement with analytical and reference results.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2022)
Editorial Material
Engineering, Aerospace
Giuseppe Quaranta, John Ekaterinaris, George Barakos, Antonio Filippone, Mark White, David Anderson, Marilena Pavel
AEROSPACE SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Aerospace
Alessandro Donizetti, Tommaso Bellosta, Andrea Rausa, Barbara Re, Alberto Guardone
Summary: This paper presents a novel level-set-based approach for modeling in-flight ice accretion, which avoids the mesh entanglements and grid intersections typical of algebraic and mesh deforming techniques. It also introduces a local ice thickness correction method to preserve the prescribed iced mass locally. The method is verified through simulations on different ice conditions and shown to be advantageous and robust compared to standard algebraic methods.
JOURNAL OF AIRCRAFT
(2023)
Article
Engineering, Aerospace
Myles Morelli, Lorenzo Beretta, Alberto Guardone, Giuseppe Quaranta
Summary: This study numerically investigates the influence of sinusoidal leading-edge characteristics on aircraft icing, showing that wavy leading edges increase localized impingement of super-cooled water droplets and affect ice shapes. The results indicate that the maximum ice thickness is found near the wave peaks and troughs, while the midsections of the waves have significantly lower levels of ice accretion.
JOURNAL OF AIRCRAFT
(2023)
Article
Mathematics, Applied
Peng Yan, Camilla Cecilia Conti, Giulio Gori, Barbara Re, Alberto Guardone
Summary: This paper numerically investigates the effect of flow non-ideality on the Mach disk pattern occurring in axisymmetric under-expanded supersonic jets. Numerical simulations of steady inviscid compressible flows are carried out by adopting the polytropic ideal gas model and improved Peng-Robinson thermodynamic model. The effects of the flow non-ideality on the Mach disk are investigated by simulating different operating conditions of under-expanded nozzle jets of five different vapors.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2023)
Article
Mathematics, Applied
Giuseppe Sirianni, Barbara Re, Remi Abgrall, Alberto Guardone
Summary: A set of strategies and numerical techniques for simulating weakly compressible two-phase flows is presented, including a pressure formulation of the full Baer-Nunziato equations and a Momentum Weighted Interpolation formulation to mitigate pressure checkerboarding. The proposed approach is thoroughly tested against analytic and experimental data.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2023)
Article
Chemistry, Analytical
Andrea Zanoni, Pierre Garbo, Pierangelo Masarati, Giuseppe Quaranta
Summary: Sensing the interaction between the pilot and the control inceptors can provide important information about the pilot's activity during flight, potentially enabling objective measurement of pilot workload, preventive actions against loss of situational awareness, and identification of adverse couplings with vehicle dynamics. This work presents an innovative pressure-sensing device integrated into conventional aircraft control inceptors. The sensor, based on frustrated total internal reflection of light, can be easily manufactured and applied to different hand pressure ranges. Laboratory calibration tests demonstrate its characteristics, while flight simulator testing focuses on objective representation of pilot's instantaneous workload.
Article
Engineering, Aerospace
Paolo Francesco Scaramuzzino, Marilena D. Pavel, Daan M. Pool, Olaf Stroosma, Max Mulder, Giuseppe Quaranta
Summary: This paper analyzes the effects of helicopter dynamics on pilot learning process and skill transfer during autorotation training. The study found significant positive transfer from hard dynamics to easy dynamics, but not vice versa. The two groups of pilots differed in control strategy, with the EHE group adjusting their strategy to align with the HEH group during the final training phase.
JOURNAL OF AIRCRAFT
(2022)
Article
Engineering, Aerospace
Vincenzo Muscarello, Giuseppe Quaranta
Summary: This paper investigates structural coupling problems for tiltrotors, considering the interaction between the flight control system and the flexible structure, as well as the potentially adverse effects on aeroservoelastic stability caused by the pilot's involuntary, high-frequency, biodynamic response. The results show that the stability of tiltrotors must be evaluated by considering both the closed loop created by the flight control system and the effect of involuntary pilot response.
JOURNAL OF THE AMERICAN HELICOPTER SOCIETY
(2021)
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)
