Article
Mechanics
Xiaonan Chen, Koji Iwano, Yasuhiko Sakai, Yasumasa Ito
Summary: This study investigated the effect of artificial very-large-scale motions (AVLSMs) generated by a dielectric-barrier-discharge plasma actuator (DBD-PA) array on the bursting phenomenon in the near-wall region. The results showed that bursting phenomenon was suppressed in the positive motions (pAVLSM) and enhanced in the negative motions (nAVLSM).
Article
Energy & Fuels
Guoqiang Xiong, Gesheng Li, Weilin Zeng, Junjie Liang
Summary: The steady flamelet method was used in the large eddy simulation (LES) of turbulent cool flames to investigate its capability. The results showed that it accurately captured the mean and variance trends for temperature, mixture fraction, and formaldehyde, as well as described the flame morphology of the two-stream flamelet form.
Article
Geosciences, Multidisciplinary
H. Dashtpeyma, B. J. MacVicar
Summary: Pool-riffle units are natural topographical elements of rivers. This study uses Large Eddy Simulations to investigate the dynamics of flow over straight riffles and proposes a physical mechanism for the observed high near-bed velocities. The results provide a novel explanation for near-bed high velocity flow observations in natural pool-riffles and reveal the significance of turbulent shear stresses in the head of a pool.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2023)
Article
Physics, Fluids & Plasmas
Razieh Jalalabadi, Thorsten Stoesser
Summary: This study examines the Reynolds and dispersive shear stresses in turbulent flow over spanwise-aligned square bars in an open channel flow. The analysis of large-eddy simulation results for two different bar spacings reveals that the contribution of Reynolds shear stress to the momentum loss is greater than that of the dispersive shear stress. However, by increasing the bars spacing, the contribution of the dispersive shear stress increases while the Reynolds shear stress contribution decreases. The study also investigates the dynamics of the flow and finds that there is a momentum source below the crest of the bars and a momentum sink above them, leading to acceleration or deceleration of flow. Furthermore, the quantification of the three components of total kinetic energy shows that the largest contribution is from the mean flow, and by increasing the bar spacing, the contributions of turbulent and wake kinetic energy increase while the kinetic energy of the mean flow decreases.
Article
Mechanics
Wen-Feng Zhou, Jun Chen
Summary: The study investigates the large-scale structure of turbulent Rayleigh-Benard convection in a slim-box using direct numerical simulations. It reveals that the large-scale circulation is primarily driven by jet flows, with a power law relationship between the Reynolds number and Rayleigh number. The characteristics of the thermal boundary layer, wall jet, and their three-layer structure are key features of turbulent RBC at moderate Rayleigh numbers.
Article
Thermodynamics
Mostafa Esmaeili, Asghar Afshari
Summary: This study numerically investigates the flow features and mixing/combustion efficiencies in a turbulent reacting jet in cross-flow using a hybrid Eulerian-Lagrangian methodology. The findings show that the main features of a reacting JICF flame can be reproduced by the large-eddy simulation (LES)/FMDF method, and increasing the momentum ratio improves mixing and combustion efficiency.
INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW
(2021)
Article
Mechanics
Yong Ji, Jie Yao, Fazle Hussain, Xi Chen
Summary: Investigation on vorticity transport in turbulent channels under large-scale active drag control reveals the significant contribution of vorticity fluctuations to frictional drag, with random and coherent components playing different roles in drag reduction. Analysis suggests that suppressing random spanwise-vorticity transport is crucial for more effective drag reduction.
Article
Engineering, Marine
Linlin Geng, Desheng Zhang, Jian Chen, Xavier Escaler
Summary: The tip leakage vortex (TLV) plays a significant role in cavitation flow and has a strong influence on overall structures and the development of other vortices. Large-eddy simulation (LES) is a valuable tool for predicting TLV behavior and showing the evolution process of TLV.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Mechanics
Xiaoliang He, Sourabh V. Apte, Shashank K. Karra, OEmer N. Dogan
Summary: Large-eddy simulations were conducted on turbulent flow in a 90 degree pipe bend at three Reynolds numbers to investigate the correlation between secondary flow motion and wall shear stresses. The study identified oscillations of Dean vortices causing swirl-switching and distinguished frequencies related to Reynolds numbers.
Article
Computer Science, Interdisciplinary Applications
Ashutosh Kumar Jaiswal, Anupam Dewan, Amitabh Bhattacharya
Summary: Scale-resolving hybrid RANS-LES models are efficient and accurate for numerically simulating wall-bounded turbulent flows. The interpolated RANS-LES solver, implemented in OpenFOAM, simultaneously evolves the RANS equations and LES equations on the same computational grid. By interpolating the turbulent eddy-viscosity, the solver corrects the mean subgrid stress and accurately predicts resolved Reynolds stresses.
COMPUTERS & FLUIDS
(2023)
Article
Mechanics
Akash Venkateshwaran, Zhuoran Li, Shooka Karimpour
Summary: Numerical simulations were conducted to study the turbulent characteristics of weak surge waves generated by the sudden removal of a gate. Large Eddy Simulation was used to investigate a range of surge Froude numbers and resolved various tempo-spatial scales down to the Hinze scale. Turbulent statistics were established using Favre-averaging, which showed that turbulent kinetic energy is mainly produced at the toe where the shear layer originates. Anisotropy analyses revealed different structures in the mixing layer and recirculating region.
Article
Acoustics
Weiqi Shen, Trushant K. Patel, Steven A. E. Miller
Summary: This study introduces a time-domain BBSAN model based on the vector Green's function solution, utilizing LES databases and Proper orthogonal decomposition to analyze shock-associated noise in off-design supersonic jets. By analyzing the predominant POD modes and noise source contour plots, the key features of BBSAN are revealed.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Mechanics
Xianxu Yuan, Fulin Tong, Weipeng Li, Jianqiang Chen, Siwei Dong
Summary: This paper investigates the wall-attached temperature structures in supersonic turbulent boundary layers using direct numerical simulations. The study finds that these structures exhibit self-similarity, with the length and width of the positive family being linear functions of the height. The superposed temperature variance decays logarithmically with wall distance, while the superposed intensity of the wall-normal heat flux in the negative family shows a logarithmic growth. Furthermore, the relative position between temperature structures of opposite signs differs significantly from the relative position between low- and high-speed streaks.
Article
Automation & Control Systems
Xiaotong Ren, Shengqiang Shen, Yong Yang, Hui Lv, Yali Guo
Summary: In this research, numerical simulations of a turbulent round jet were performed using large eddy simulation (LES) and the results were compared to Reynolds-averaged Navier-Stokes (RANS). The turbulence statistics are independent of the Reynolds number for Re >= 1104. A three-dimensional turbulent round jet near the exit, with a Reynolds number of 6.2104, was simulated to better represent real-world engineering applications. The comparison of LES and RANS turbulence models with experimental data showed that LES provides more accurate predictions of the core area and length of the jet core, and its turbulence statistics agree with experimental results.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Mathematics, Applied
Qiming Zhu, Minjiang Zhu, Jinhui Yan
Summary: This paper extends the application of isogeometric analysis (IGA) to particle-laden flows based on Eulerian-Eulerian description. By using non-uniform rational B-spline (NURBS) functions and a residual-based variational multiscale (VMS) formulation, the coupled systems of equations are solved, enabling accurate prediction of flow/particle statistics with a relatively lower mesh resolution.
MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES
(2022)
Article
Engineering, Ocean
Aristos Christou, Zhihua Xie, Thorsten Stoesser, Pablo Ouro
Summary: In this study, the Hydro3D in-house large-eddy simulation code was refined to investigate wave structure interaction. The code accurately simulated solitary waves generation and propagation in a numerical wave tank, as well as wave interaction with both infinitely wide and finite square plates. Three-dimensional effects, such as span-wise flow and unique flow structures near the plate, were identified, along with variations in hydrodynamic forces and free-surface elevations when the plate is fixed at different angles of attack.
APPLIED OCEAN RESEARCH
(2021)
Article
Engineering, Civil
V Sriram, Shagun Agarwal, Shiqiang Yan, Zhihua Xie, Shaswat Saincher, Torsten Schlurmann, Qingwei Ma, Thorsten Stoesser, Yuan Zhuang, Bo Han, Weiwen Zhao, Xiaotong Yang, Z. Li, Decheng Wan, Yi Zhang, Bin Teng, Dezhi Ning, Ningbo Zhang, Xing Zheng, Guochun Xu, Jiaye Gong, Yunbo Li, Kangping Liao, Wenyan Duan, Ronggui Hann, Windiman Asnim, Zana Sulaiman, Zhongbing Zhou, Jianmin Qin, Yucheng Li, Zhiwei Song, Xiaofan Lou, Lin Lu, Changfu Yuan, Yuxiang Ma, Congfang Ai, Guohai Dong, Hanbing Sun, Qiang Wang, Zhi-Tao Zhai, Yan-Lin Shao, Zaibin Lin, Ling Qian, Wei Bai, Zhihua Ma, Pablo Higuera, Eugeny Buldakov, Dimitris Stagonas, Santiago Martelo Lopez, Aristos Christou, Pengzhi Lin, Yanyan Li, Jinshu Lu, Sa Young Hong, Yoon-Jin Ha, Kyong-Hwan Kim, Seok-Kyu Cho, Dong-Min Park, Wojciech Laskowski, Claes Eskilsson, Mario Ricchiuto, Allan P. Engsig-Karup, Lin Cheng, Jinhai Zheng, Hanbin Gu, Guangnian Li
Summary: This paper presents a comparative study on the interaction between focused waves and a fixed cylinder, using 20 numerical solvers developed by various universities. The qualitative and quantitative comparisons based on wave probe and pressure probe time histories and spectral components show differences among different solvers. The relative error analysis indicates variations in performance among the solvers, providing insights for industrial applications.
INTERNATIONAL JOURNAL OF OFFSHORE AND POLAR ENGINEERING
(2021)
Article
Thermodynamics
Arthur Hajaali, Thorsten Stoesser
Summary: The mean and instantaneous flow separation of two different three-dimensional asymmetric diffusers were analyzed using large-eddy simulations, showing good agreement with experimental data. The study further quantifies flow separation behavior and unsteadiness, revealing the volume portion in which the instantaneous reversal flow evolves. Analysis of power density spectra of time series indicates the periodicity of the growth and reduction phases of flow separation within the diffusers.
FLOW TURBULENCE AND COMBUSTION
(2022)
Article
Engineering, Marine
Xingsen Guo, Tingkai Nian, Thorsten Stoesser
Summary: This paper investigates the impact forces induced by submarine landslides on a golfball-type dimpled pipeline surface using a computational fluid dynamics approach. The study finds that the golfball-type dimpled pipelines experience reduced drag forces and suppress lift force variations. A methodology for predicting the drag reduction and necessary conditions for lift force periodic vibrations are provided. Additionally, the paper reveals the full life cycle of vortices shed from the pipeline and the hydrodynamics during landslides impact on pipelines.
Article
Engineering, Marine
Xingsen Guo, Thorsten Stoesser, Tingkai Nian, Yonggang Jia, Xiaolei Liu
Summary: This paper investigates the influence of pipeline surface roughness on the interaction between submarine landslides and pipelines. The study establishes a methodology to estimate peak impact forces, providing a basis for risk assessment of submarine pipelines.
Article
Computer Science, Interdisciplinary Applications
Zhihua Xie, Pengzhi Lin, Thorsten Stoesser
Summary: A conservative and consistent three-dimensional Cartesian cut-cell method is proposed to reduce spurious pressure oscillations in moving body simulations. The method improves the moving body algorithm and enforces strict conservation of mass and momentum through pressure-velocity coupling. A consistent mass and momentum flux computation is employed, and an implicit time integration scheme is used to prevent numerical instability.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Mechanics
Yan Liu, T. Stoesser, H. Fang
Summary: This study investigates the effect of secondary currents on friction factor, statistics, and large-scale turbulent motion in partially filled pipes using large-eddy simulations. The results show that secondary currents originate from the corner between the free surface and the pipe walls, and their presence reduces the friction factor and the strength of near-wall structures. Therefore, partially filled pipe flows have lower drag and turbulent energy compared to fully filled pipe flows.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Engineering, Civil
Congfang Ai, Yuxiang Ma, Changfu Yuan, Zhihua Xie, Guohai Dong, Thorsten Stoesser
Summary: This paper presents a simulation study of a solitary wave propagating over a submerged horizontal plate using a non-hydrostatic model and a high-resolution advection scheme. The results show that the length of the plate has a significant influence on the characteristics of vortex shedding and evolution, with longer plates resulting in more pronounced vortex structures.
JOURNAL OF HYDRAULIC RESEARCH
(2022)
Article
Engineering, Marine
Congfang Ai, Yuxiang Ma, Changfu Yuan, Zhihua Xie, Guohai Dong, Thorsten Stoesser
Summary: This paper presents a three-dimensional non-hydrostatic model for predicting the interaction between nonlinear waves and fixed floating structures. A new numerical algorithm is proposed to handle floating structures, and the model is validated by comparing its results with experimental data and other models.
Article
Mechanics
Yan Liu, Thorsten Stoesser, Hongwei Fang
Summary: This study investigates the response of turbulent flow and water surface fluctuations in partially filled pipes through large eddy simulations. The results show that as the water depth increases, the strength of the main secondary flow and the magnitude of water surface fluctuations also increase. Pre-multiplied spectra provide further evidence of the origin of the surface waves. Analysis of the wavenumber-frequency spectra reveals different types of surface waves.
Article
Environmental Sciences
Chenwei Zhao, Pablo Ouro, Thorsten Stoesser, Subhasish Dey, Hongwei Fang
Summary: Numerical simulations were conducted to explore the effects of natural bed roughness on bedload transport. The results show that as bed roughness increases, there is a shift in the velocity profiles, an increase in Reynolds stresses, and the fragmentation of coherent structures. The resting time of saltating particles increases while their saltation length, velocity, and angular velocity decrease.
WATER RESOURCES RESEARCH
(2022)
Article
Engineering, Civil
Filipa Adzic, Thorsten Stoesser, Yan Liu, Zhihua Xie
Summary: Large-eddy simulations were performed to study the characteristics of supercritical flow in a straight-wall, open-channel contraction. The results revealed that secondary currents in the contraction redistributed momentum, resulting in local up-and down-flows, and the energy loss was mainly caused by pressure drag.
JOURNAL OF HYDRAULIC RESEARCH
(2022)
Article
Engineering, Ocean
Xingsen Guo, Thorsten Stoesser, Cheng Zhang, Cuiwei Fu, Tingkai Nian
Summary: This study investigates the interaction between submarine landslides, ambient water, and pipelines using computational fluid dynamics (CFD) modeling and physical flume experiments. The effects of different boundary conditions on the impact forces on pipelines are explored, and the mechanism behind these force changes is explained through the analysis of velocity field, pressure field, and streamlines. A method for determining boundary conditions is proposed, providing a basis for optimizing CFD modeling in submarine landslide-pipeline interactions.
APPLIED OCEAN RESEARCH
(2022)
Article
Computer Science, Interdisciplinary Applications
Xingsen Guo, Thorsten Stoesser, Defeng Zheng, Qianyu Luo, Xiaolei Liu, Tingkai Nian
Summary: In this study, the method of computational fluid dynamics (CFD) was used to simulate a fluidized submarine landslide with shear thinning non-Newtonian fluids under different contact conditions. The accuracy of the CFD method was validated and various experiments were systematically performed. The stress state and causes of the submarine landslide mass during its movement in ambient water were revealed, and the submarine landslide-seabed contact relation was identified as a decisive influencing factor. Furthermore, a methodology based on energy conservation was presented to predict the run-out distance of the submarine landslide mass, and equations to quantify the process were established and validated by numerical results. This provides a significant basis for the prediction of marine engineering geological and hydrodynamic hazards related to submarine landslides.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Physics, Fluids & Plasmas
Razieh Jalalabadi, Thorsten Stoesser
Summary: This study examines the Reynolds and dispersive shear stresses in turbulent flow over spanwise-aligned square bars in an open channel flow. The analysis of large-eddy simulation results for two different bar spacings reveals that the contribution of Reynolds shear stress to the momentum loss is greater than that of the dispersive shear stress. However, by increasing the bars spacing, the contribution of the dispersive shear stress increases while the Reynolds shear stress contribution decreases. The study also investigates the dynamics of the flow and finds that there is a momentum source below the crest of the bars and a momentum sink above them, leading to acceleration or deceleration of flow. Furthermore, the quantification of the three components of total kinetic energy shows that the largest contribution is from the mean flow, and by increasing the bar spacing, the contributions of turbulent and wake kinetic energy increase while the kinetic energy of the mean flow decreases.