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Prediction of Wind-Pressure Coefficients on Circular Elevated-Tanks Through the Novel CFD-ANN Model for Various Building-Interference Circumstances Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-03-13 Soumya Mukherjee, Jalla Sandeep Kumar Reddy, Dilip Kumar Singha Roy
The authors have studied the wind-shielding effect on circular elevated tanks with computational fluid dynamics (CFD) analyses, caused by rectangular plan-shaped buildings, which alter wind load si...
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HALO3D: An All-Mach Approach to Hypersonic Flows Simulation, Part II Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-02-22 Shrutakeerti Mallikarjun, Vincent Casseau, Gan Yang, John Y. Huang, Wagdi G. Habashi, Song Gao, Abolfazl Karchani
This paper is Part II of the two-paper series ‘HALO3D: An All-Mach Approach to Hypersonic Flows Simulation’ presenting advances in a monolithic flow simulation software for the design of high-speed...
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An Accurate and Robust Line-Hybrid Method for Hypersonic Heating Predictions Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-22 Ye Zhang, Wenjia Xie, Weijie Ren, Zhengyu Tian
As Computational Fluid Dynamics (CFD) progresses rapidly, there is a growing demand for precise prediction of aerodynamic heating in hypersonic flows, which remains a considerable challenge. In thi...
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High-Order WENO-based Semi-Implicit Projection Method for Incompressible Turbulent Flows: Development, Accuracy, and Reynolds Number Effects Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-15 Thi Quynh Nguyen, Hyung Taek Ahn, Christos Kavouklis
A novel high-order projection method is presented in this study for the simulation of incompressible turbulent flows, utilising weighted essentially non-oscillatory (WENO) schemes. Spatial discreti...
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Numerical Investigation of Gasper Air Jet Dynamics in an Aircraft Cabin Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-15 Vinod Kumar Srinivasa, Subhaschandra Kattimani, Ganga Reddy C.
Computational fluid dynamics (CFD) is used to analyze the jet interaction of side-vent and gaspers and their influence on cough jets in aircraft cabins. A control device is designed and proposed to...
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Multi-Viscosity Physics-Informed Neural Networks for Generating Ultra High Resolution Flow Field Data Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-15 Sen Zhang, Xiao-Wei Guo, Chao Li, Ran Zhao, Canqun Yang, Wei Wang, Yanxu Zhong
To address the limited generalisation ability issue of physics-informed neural networks, we propose a multi viscosity physics-informed neural networks (μ-PINNs), along with two tailored training st...
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Identification of Oil and Gas Two-Phase Flow Patterns in Aero-Engine Bearing Chambers Based on Kriging Method Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-15 Jingkui Li, Binjie Qu, Yuming Qian, Zhibin Liu, Zhandong Li
The identification of the flow pattern within the bearing chamber's oil and gas two-phase flow is crucial for its lubrication design. Aiming at the lack of accuracy and universality of the current ...
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A High-Order Compact Gas-Kinetic Scheme in a Rotating Coordinates Frame and on Sliding Mesh Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-09 Yue Zhang, Xing Ji, Kun Xu
This paper extends the high-order compact gas-kinetic scheme (CGKS) to flow simulations on a rotating coordinate frame. The kinetic equation with the inclusion of centrifugal and Coriolis accelerat...
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Time-Accurate Solution of Unsteady Flows in an Implicit Solver Using Block LUSGS Method Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-09 M. R. Nived, Poreddy Pavan Kumar Reddy, Vinayak Eswaran
Implicit solvers based on the lower-upper symmetric Gauss–Seidel (LUSGS) method are widely used in Computational Fluid Dynamics (CFD) codes to obtain steady-state solutions using large false-transi...
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Adjoint Based Aerodynamic Shape Optimisation Using Kinetic Meshfree Method Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-09 Keshav S. Malagi, Nischay R. Mamidi, Nemili Anil, Vasudev Ramesh, Suresh M. Deshpande
The gradient based optimisation algorithms combined with the finite volume or element based adjoint approaches have been very successful in aerodynamic shape optimization (ASO). The meshfree least ...
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Turbulence Modelling for SWTBLI with Expansion Wave Interference Inside Scramjet Inlets Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2024-01-09 Kavan M. Prabtani, Rajesh Ranjan
An accurate prediction of the flowfield inside the scramjet inlet/isolator is crucial for a stable and reliable aerodynamic design. However, the complex phenomena such as shock wave-expansion wave ...
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A Shock Sensor Based on Image Segmentation with Application to a Hybrid Central/WENO Scheme Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-11-30 Nasreddine Bouguellab, Smail Khalfallah, Boubakr Zebiri, Nassim Brahmi
A novel shock sensor based on image segmentation is proposed for flows with shock or detonation waves. It consists of a function computed based on the numerical Schliren formulation, which is the a...
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A Unified Grid Approach Using Hamiltonian Paths for Computing Aerodynamic Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-11-30 Yong Su Jung, Bharath Govindarajan, James Baeder
A solution algorithm using Hamiltonian paths is presented as a unified grid approach for rotorcraft applications. Hidden line structures are robustly identified on general two- and three-dimensiona...
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Investigation of Low and High-Speed Fluid Dynamics Problems Using Physics-Informed Neural Network Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-11-30 Anubhav Joshi, Alexandros Papados, Rakesh Kumar
In this work, we have employed physics-informed neural networks (PINNs) to solve a few fluid dynamics problems at low and high speeds, with a focus on the latter. For high-speed fluid dynamics prob...
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Prediction of Flow Field Over Airfoils Based on Transformer Neural Network Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-11-30 Jianbo Zhou, Rui Zhang, Lyu Chen
Airfoil flow field data acquisition is pivotal to the study of aerodynamics, traditionally relying on time-consuming computational fluid dynamics simulations or expensive wind tunnel tests. Herein,...
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Fluid Flow Modelling Using Physics-Informed Convolutional Neural Network in Parametrised Domains Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-10-10 Ondřej Bublík, Václav Heidler, Aleš Pecka, Jan Vimmr
We design and implement a physics-informed convolutional neural network (CNN) to solve fluid flow problems on a parametrised domain. The goal is to compare the effectiveness of training based solel...
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A Lattice Boltzmann Front-Tracking Interface Capturing Method based on Neural Network for Gas-Liquid Two-Phase Flow Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-09-04 Bozhen Lai, Zhaoqing Ke, Zhiqiang Wang, Ronghua Zhu, Ruifeng Gao, Yu Mao, Ying Zhang
This paper presents a new method that accurately captures the interface of gas–liquid two-phase flow using a neural network-based lattice Boltzmann front-tracking interface capturing method. The mo...
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Wall-Resolved Large-Eddy Simulation of Flow Over a Three-Dimensional Gaussian Bump Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-08-23 Donald P. Rizzetta, Daniel J. Garmann
Wall-resolved large-eddy simulations were carried out for the flow over a Gaussian bump configuration. The geometry and flow conditions were motivated by an experimental investigation, which was co...
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Verification of a Pressure-Based Compressible Flow Solver Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-08-17 João Muralha, Luis Eça, Christiaan Klaij
This paper presents Solution Verification exercises with the pressure-based compressible flow solver ReFRESCO for five test cases available in the NASA Turbulence Modeling Resource: the two-dimensi...
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A New Third-Order Finite Difference WENO Scheme to Improve Convergence Rate at Critical Points Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-08-10 Xiaogang Li, Tian Xia, Yuxi Deng, Siqi Yang, Yonbin Ge
In this work, a new, improved third-order finite difference weighted essentially non-oscillatory scheme is presented for one- and two-dimensional hyperbolic conservation laws and associated problems. The parameter p which is regulate dissipation is introduced in the nonlinear weights in the framework of the conventional WENO-Z scheme, and the higher-order global smoothness indicator is obtained by
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Parallel Computation Using Non-Overlapping Domain Decomposition Coupled with Compact Local Integrated RBF for Navier–Stokes Equations Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-06-28 Nam Pham-Sy, Canh-Dung Tran
A non-overlapping domain decomposition-based parallel algorithm coupled with a compact local integrated radial basis function (CLIRBF) method is developed for solving Navier-Stokes equations. For this approach, a problem is divided into subdomains. In each sub-domain, a CLIRBF scheme is applied to solve the Navier-Stokes equations of flows. A relaxation factor is used at the interface between sub-domains
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Shape Optimization and Flow Analysis of Supersonic Nozzles Using Deep Learning Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-06-21 Aref Zanjani, Amir Mahdi Tahsini, Kimia Sadafi, Fatemeh Ghavidel Mangodeh
Shape optimisation of supersonic nozzles is of crucial importance in designing propulsion systems and space thrusters. In order to optimise the profile of a supersonic nozzle, the properties of the flow inside the nozzle should be obtained. This paper proposes and verifies a new methodology for analysing flows and designing supersonic nozzles. Flow analysis has been conducted using the method of characteristics
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Finite Element Numerical Simulation of Local Scour of a Three-Dimensional Cylinder under Steady Flow Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-06-13 Dawei Peng, Lanhao Zhao, Chuan Zhou, Jia Mao
Pile safety has received increasing attention in marine engineering, especially in the field of local scour. In this paper, a finite element numerical model is established for local scour around a cylinder in steady currents. The flow is described by unsteady Reynolds–averaged Navier–Stokes equations with a traditional k−εk−ε turbulent closure model. The proposed scour model takes bed load into account
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A Momentum-Conserving Weakly Compressible Navier–Stokes Solver for Simulation of Violent Two-Phase Flows with High Density Ratio Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-04-20 Kai Yang, Takayuki Aoki
A consistent and conservative formulation for mass and momentum transport is proposed in the context of simulating incompressible two-phase flows by using weakly compressible method. Combined with the evolving pressure projection method to prevent oscillation of the solution induced by the acoustic wave, this solver aims at a robust and accurate computation of violent two-phase flows with a high density
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Evaluation Method for the Reasonableness of Countermeasures for Defective Products in the Negative-Pressure Molding Mechanism Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-03-31 Guodong Zhu, Yong Wang, Jianhui Liu, Ji Zhou, Zhenghu Mo
We propose a new digital evaluation model for the negative-pressure molding mechanism, which is used to verify the feasibility of improvement measures for quality problem of the pad. The gas–solid flow in the negative pressure molding system facing the pad of diapers at the molding surface under different outlet pressures is studied using CFD-DEM bidirectional coupling simulation method. Aiming at
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Numerical Study of Compressible Wall-Bounded Turbulence – the Effect of Thermal Wall Conditions on the Turbulent Prandtl Number in the Low-Supersonic Regime Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-03-30 David J. Lusher, Gary N. Coleman
ABSTRACT Direct numerical simulation is used to determine the turbulent Prandtl number Prt above cold (isothermal) and hot (adiabatic) walls in a family of low-supersonic channel flows. A range of mean temperature/density variations, corresponding to effective/edge Mach numbers between 1.1 to 2.2, and wall-variable-based Reynolds number Reτw from 73 to 3800, is considered. The adiabatic condition is
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Correction Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-03-26
Published in International Journal of Computational Fluid Dynamics (Vol. 36, No. 9, 2022)
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Application of Gas-Kinetic Scheme for Continuum and Near-Continuum Flow on Unstructured Mesh Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-03-21 Guang Zhao, Chengwen Zhong, Sha Liu, Yong Wang, Congshan Zhuo
A gas-kinetic scheme (GKS) with kinetic boundary condition based on unstructured mesh is present here. In the GKS method, the solid wall boundary conditions can be constructed by virtue of the gas distribution function, which is similar to the diffuse-scattering rule used in the other kinetic schemes. The kinetic boundary condition has a concise form and easy to implement. The use of unstructured mesh
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Numerical Simulations and Design Optimization of Compressor Cascade Flow Using One Equation and Wray-Agarwal Turbulence Model Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-03-09 Zhihui Li, Ramesh K. Agarwal
The unsteady simulations are conducted, and the computed results with WA model are compared with the experimental data in conjunction with the simulation results obtained using traditional models. It is shown that on the mid-span sections of the cascade airfoils the distributions of near-wall static pressure coefficients from each turbulence model agree well with the experimental data. On the lower
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On the Contribution of Wall Distance Fields to the Adjoint of a RANS Model Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-16 Matteo Ugolotti, Paul Orkwis, Nathan Wukie
The adjoint method has been extensively used in many areas of CFD such as gradient-based shape optimisation. When utilising the RANS equations for simulating turbulent flows, the adjoint method requires a scrupulous differentiation of the RANS equations, including the wall distance contribution. This can be a challenging task and a potential source of inaccuracy for functional sensitivities if not
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Machine Learning in CFD Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Paul D. Orkwis, Mahdi Pourbagian
Published in International Journal of Computational Fluid Dynamics (Vol. 36, No. 7, 2022)
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Training a Neural-Network-Based Surrogate Model for Aerodynamic Optimisation Using a Gaussian Process Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Yousef Ghazi, Nahla Alhazmi, Radek Tezaur, Charbel Farhat
A two-step idea is presented for efficiently training a neural network (NN) surrogate of a parametric, high-fidelity, high-dimensional computational fluid dynamics model (HDM). It consists first in using a Gaussian process, an acquisition function, the HDM, and a scalar quantity obtained by post-processing the HDM to adaptively sample the parameter space. Next, a NN is trained for a quantity of interest
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On the Generalizability of Machine-Learning-Assisted Anisotropy Mappings for Predictive Turbulence Modelling Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Ryley McConkey, Eugene Yee, Fue-Sang Lien
Several machine learning frameworks for augmenting turbulence closure models have been recently proposed. However, the generalizability of an augmented turbulence model remains an open question. We investigate this question by systematically varying the training and test sets of several models. An optimal three-term tensor basis expansion is used to develop a model-agnostic data-driven turbulence closure
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Nonintrusive Reduced Order Modelling of Convective Boussinesq Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Pedram H. Dabaghian, Shady E. Ahmed, Omer San
In this paper, we formulate three nonintrusive methods and systematically explore their performance in terms of the ability to reconstruct the quantities of interest and their predictive capabilities. The methods include deterministic dynamic mode decomposition, randomised dynamic mode decomposition and nonlinear proper orthogonal decomposition (NLPOD). We apply these methods to a convection dominated
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Numerical Assessment of a Nonintrusive Surrogate Model Based on Recurrent Neural Networks and Proper Orthogonal Decomposition: Rayleigh–Bénard Convection Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Saeed Akbari, Suraj Pawar, Omer San
Recent developments in diagnostic and computing technologies offer to leverage numerous forms of nonintrusive modelling approaches from data where machine learning can be used to build computationally cheap and accurate surrogate models. To this end, we present a nonlinear proper orthogonal decomposition (POD) framework, denoted as NLPOD, to forge a nonintrusive reduced-order model for the Boussinesq
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Multi-Fidelity Machine Learning Applied to Steady Fluid Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Kazuko W. Fuchi, Eric M. Wolf, David S. Makhija, Christopher R. Schrock, Philip S. Beran
A machine learning method to predict steady external fluid flows using elliptic input features is introduced. Using data from as few as one high-fidelity simulation, the proposed method produces models generalisable under changes to boundary geometry by using solutions to elliptic boundary value problems over the flow domain as the model input, instead of Cartesian coordinates of the domain. Training
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Machine Learning to Predict Aerodynamic Stall Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Ettore Saetta, Renato Tognaccini, Gianluca Iaccarino
A convolutional autoencoder is trained using a database of airfoil aerodynamic simulations and assessed in terms of overall accuracy and interpretability. The goal is to predict the stall and to investigate the ability of the autoencoder to distinguish between the linear and non-linear response of the airfoil pressure distribution to changes in the angle of attack. After a sensitivity analysis of the
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A Model-Constrained Tangent Slope Learning Approach for Dynamical Systems Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-02-10 Hai V. Nguyen, Tan Bui-Thanh
Real-time accurate solutions of large-scale complex dynamical systems are in critical need for control, optimisation, uncertainty quantification, and decision-making in practical engineering and science applications, especially digital twin applications. This paper contributes in this direction a model-constrained tangent slope learning (mcTangent) approach. At the heart of mcTangent is the synergy
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Vorticity Confinement Technique and Blade Element Method for Accurate Propeller Modelling Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-01-10 Y. Chandukrishna, T. N. Venkatesh
Traditional CFD techniques are not effective in preserving wakes and vortices over larger distances and for longer times. Vorticity Confinement (VC) technique helps counter the numerical diffusion to preserve wakes and vortices. In the current study, VC was used to accurately model the propeller flow using two different propeller modelling techniques after being implemented into SU2, an open-source
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Numerical Investigation of a Simplified Wing–body Junction Flow Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2023-01-06 Ziyan Wei, Jie Li, Songxiang Tang
The flow past a simplified wing-body junction configuration is simulated using a shear layer adaptive improved delayed detached-eddy-simulation (SLA-IDDES) approach in which an appropriate subgrid lengthscale is adopted in the boundary region, where the grid may be strongly anisotropic, to prevent the excessive generation of subgrid-scale eddy viscosity. The numerical results show overall good agreement
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Heat Transfer of Aggregate in a Drying Drum Based on the Multi-Scale Model and Fluid-Solid Coupling Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-12-29 Zhiyong Li, Lingying Zhao, Min Ye
The simulation of engineering research is difficult, especially the engineering problem of the large differences between the size of the equipment and materials processed. At present, two methods are used to solve this problem, i.e. the equal scale reduction model and the study of only a part of it, which makes it inconsistent with the actual situation. To find a better way to improve this problem
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Data-Driven Proxy Modeling of Water Front Propagation in Porous Media Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-12-27 Behzad Saberali, Kai Zhang, Naser Golsanami
In the water flooding process, determining the location of the injected water front is as one of the most critical variables, which is the basis of many subsequent predictions. Despite the importance and use of this parameter in a vast range of flooding-related assessments, there are no alternative methods to traditional analytical modeling or time-consuming numerical 3D simulation for its determination
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Study of Falling Condensate Droplets on Parallelepiped Solid Surface Using Hybrid 3D MRT-LBM Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-12-12 Salaheddine Channouf, Mohammed Jami
The present work focuses on the development of the 3D MRT-LBM computational method to simulate a droplet formed by the condensation of a gas at a saturation temperature. The droplet falls by the effect of its volume (body force) and collides with a solid surface of parallelepiped shape for different values of 0.25 ≤κ≤0.95. This study presents the evolution of the drop from its formation on the upper
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Implementation and Validation of the SST Delayed eXtra-LES Model for Complex Turbulent Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-12-12 Alessia Fracassi, Remo De Donno, Antonio Ghidoni, Gianmaria Noventa
This work presents a Delayed version of the hybrid RANS-LES eXtra Large Eddy Simulation (SST DX-LES) model for the simulation of turbulent flows. In particular, in the proposed model the Shear Stress Transport (SST) k-ω turbulence model replaces the TNT k-ω model, and a shielding function is introduced to avoid the Modelled Stress Depletion (MSD) and the related Grid-Induced Separation (GIS), typical
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Finite Difference and Reinitialization Methods with Level Set to Interfacial Area Transport Equations for Gas–Liquid Two-Phase Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-12-09 Kyohei Mizuno, Makoto Asahara, Tomohiro Kamiya, Takeshi Miyasaka
For the direct simulation of liquid atomization processes affected by surface tension, the level-set method was suitable, owing to the ease of estimating normal vectors and interface curvatures. However, the mass is not conserved in the original method because of errors in the interfacial advection evaluation. Therefore, previous studies have developed the interfacial advection equation and the interfacial
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A Numerical Investigation of the Dominant Characteristics of A Transonic Flow Over A Hemispherical Turret Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-11-23 Songxiang Tang, Jie Li, Ziyan Wei
The transonic characteristics of a flow over a hemispherical turret with a freestream Mach number M∞ of 0.8 are numerically studied. The flow field is simulated using the improved delayed detached eddy simulation (IDDES) with a modified sub-grid scale. The results using the adopted medium and fine grids, including for the mean pressure coefficients and the incoming boundary layer, match experimental
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Electrically Conducting Fluid Flow and Electric Potential in a Square Cavity Subjected to a Point Magnetic Source Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-11-02 Pelin Senel, Munevver Tezer-Sezgin
ABSTRACT Magnetohydrodynamics (MHD) flow in cavities subjected to both the magnetisation and the Lorentz forces due to a point magnetic source is studied. The governing PDEs are derived and iteratively solved by the dual reciprocity boundary elements method (DRBEM) with linear elements. It is shown that the magnetic field decelerates the axial flow around the point magnetic source, and a further increase
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Entropy Generation Parallel Analysis and Optimised Efficiency of a Wavy Solar Collector Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-10-10 Surabhi Nishad, Rama Bhargava
The current paper is aimed to study entropy generation analysis and natural convective flow of CuO-water based nanofluid filled inside wavy solar collector with right-angled triangular cross sectional area. The flow is assumed to be steady, laminar and incompressible with double diffusive convection. The set of governing equations are the conservation of mass, momentum, energy and concentration which
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An Immersed Boundary Method Based on Parallel Adaptive Cartesian Grids for High Reynolds Number Turbulent Flow Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-08-16 Yuchen Yang, Xinyu Qi, Zhenming Wang, Jianming Liu, Ning Zhao
In this paper, a set of parallelised adaptive hierarchical Cartesian-based immersed boundary methodology is developed for high Reynolds number compressible flow. First, a robust and efficient grid generation method based on the separation axis theorem for arbitrary geometry is presented for automatic Cartesian grid generation. Second, an immersed boundary method (IBM) is presented coupling with wall
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Parallel Domain Decomposition of a FEM-based Tool for Numerical Modelling Mineral Slurry-like Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-08-11 Sergio Peralta, Jhon Córdova, Cesar Celis, Danmer Maza
The main parallelisation related features of a computational tool based on the finite element method (FEM) for the numerical modelling of mineral-slurry like flows are described in this work. In particular, both the domain decomposition method (DDM) and the processes communication strategy employed are discussed in detail. The DD algorithm is based on the iterative update of the boundary conditions
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SPH Modelling of a Dike Failure with Detection of the Landslide Sliding Surface and Damage Scenarios for an Electricity Pylon Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-08-11 Andrea Amicarelli, Emanuela Abbate, Antonella Frigerio
The 3D SPH code SPHERA (RSE SpA) simulates the triggering and runout stages of a full-scale earth-filled dike failure with coastal flood. The code formulation is consistent with the Kinetic Theory of Granular Flow KTGF and requires no tuned input. The main Landslide Sliding Surface LSS within the dike is detected from the field of the quadratic invariant of the strain-rate tensor. The comparison with
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An Investigation of Uncertainty Propagation in Non-equilibrium Flows Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-08-02 Tianbai Xiao
ABSTRACT Considerable uncertainties can exist between the field solutions of coarse-grained fluid models and the real-world flow physics. To study the emergence, propagation, and evolution of uncertainties poses great opportunities and challenges to develop both sound theories and reliable numerical methods. In this paper, we study the stochastic behaviour of multi-scale gaseous flows from molecular
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Recent Japanese Progress on Data Assimilation and Optimal Design by CFD Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14
Published in International Journal of Computational Fluid Dynamics (Vol. 36, No. 2, 2022)
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Shape Optimisation of a Heat Source in a Thermal Convection Field Considering Perimeter Constraint Condition Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14 Kaito Wada, Takahiko Kurahashi
In this study, we present an investigation of shape optimisation analysis for a heat convection problem taking into account perimeter constraint condition. The incompressible Navier–Stokes equation using the Boussinesq approximation, the equation of continuity and the energy equation are employed for the governing equations in the heat convection field. The mixed interpolation method is applied to
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Data Assimilation of Water Elevation in Shallow Water Flow Based on the Extended Kalman Filter FEM Using Measurement Data from Image Analysis Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14 Takahiko Kurahashi, Kohei Ikarashi, Toshiaki Kenchi, Toshihiko Eto
In this paper, we present a data assimilation analysis in a shallow water flow field considering shoreline movement, based on the extended Kalman filter finite element method (extended Kalman filter FEM). It is known that if the combined method of the Kalman filter and the finite element method(FEM) is employed, a solution can be obtained that is closer to the practical observed value than that based
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Optimal Design for Suppressing Time Fluctuation Part of Two-Dimensional Jet in Crossflow Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14 Takashi Nakazawa, Takashi Misaka, Yosuke Hasegawa
This paper proposes a shape optimisation method for suppressing a time fluctuation part of the two-dimensional jet-in-cross flow. Previously, the author has formulated a shape optimisation problem for suppressing transient fluids using Snapshot proper orthogonal decomposition (POD). This study extends it to a two-dimensional jet-in-cross flow. For this purpose, the eigenvalues of Snapshot POD are integrated
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Augmentation of Cross-Sectional Spray Measurements with Discrete Droplet Model Using Ensemble Kalman Filter Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14 Shun Takahashi, Takashi Misaka, Shotaro Nara, Naoki Sugiyama, Tetsuo Nohara, Yuiki Kuramoto, Yuki Kawamoto, Akira Obara, Rina Osada, Asuka Kikuchi, Masayuki Ochiai, Kazuo Osumi, Naoya Ishikawa
Spray flows containing droplets and particles are used in various industrial fields. In this study, we investigate an efficient and reliable way to predict the spray flow of droplets by combining the discrete droplet model (DDM) with ensemble data assimilation for application to such industrial problems. The aim is to augment cross-sectional measurements such as particle image velocimetry (PIV) with
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Shape Optimisation of Fluid-Structure Interactive Field Considering Geometrically Nonlinear Structure Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14 Eiji Katamine, Ryuga Kawai, Yasushi Yoshida
This paper presents a numerical solution to a shape optimisation of stationary fluid-structure-interactive (FSI) fields. The minimisation problem for total dissipation energy in the viscous flow field and the mean compliance minimisation problem in order to achieve stiffness maximisation in the structural field are considered for the shape optimisation. In the FSI analysis, a weak coupled analysis
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Low-Grid-Resolution-RANS-Based Data Assimilation of Time-Averaged Separated Flow Obtained by LES Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-14 Masamichi Nakamura, Yuta Ozawa, Taku Nonomura
ABSTRACT The objective of this study is to obtain accurate flow field analysis results in a short computational time by using data assimilation, which increases the accuracy of Reynolds averaged Navier-Stokes (RANS) simulations with low grid resolution. The large-eddy simulation (LES) results are assimilated into RANS simulations. In those simulations, the turbulence-model parameters are optimised
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Influence of Turbulent Inlet Boundary Condition on Large Eddy Simulation Over a Flat Plate Boundary Layer Int. J. Comput. Fluid Dyn. (IF 1.3) Pub Date : 2022-07-11 Yi Wang, Giulio Vita, Bruño Fraga, Chenghao Lyu, Jianchun Wang, Hassan Hemida
There are different methods for setting the inlet boundary condition (IBC) in large eddy simulation (LES). However, different methods applied in the same simulation result in different results. In this study, the influence of setting the IBC in the LES with the Lund method, the divergence-free synthetic eddies method (DFSEM), and the digital filter method (DFM) on the simulation of the boundary layer