Article
Engineering, Mechanical
Tausif Jamal, Varun Chitta, D. Keith Walters
Summary: This study investigates various hybrid RANS-LES models for simulating flow over a three-dimensional axisymmetric hill. The results show that eddy-viscosity-based HRL models can improve predictions over comparable RANS models, but only when the development of turbulent velocity fluctuations in the separated shear layer and recirculation region are well resolved.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2021)
Article
Mechanics
Sparsh Ganju, Sean C. C. Bailey, Christoph Brehm
Summary: Direct numerical simulations are used to investigate incompressible turbulent channel flow over smooth and sinusoidal roughness walls. The study examines the effects of roughness amplitude and wavelength on the flow, and finds that the interaction between the shear layer and roughness significantly influences the flow.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Jianyu Wang, Guojian He, Subhasish Dey, Hongwei Fang
Summary: This study investigated the interaction between flow and submerged flexible vegetation through numerical simulation, revealing the formation of alternate vortices at the flow-vegetation interface, resulting in wave-like oscillations of the vegetation canopy. The study also demonstrated the effects of flow velocity, vegetation spacing, and relative density on the characteristics of vegetation oscillations.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Jianyu Wang, Guojian He, Subhasish Dey, Hongwei Fang
Summary: This study presents a three-dimensional numerical model for the interaction of flow with submerged flexible vegetation, successfully simulating the interaction between flow and highly flexible vegetation. Experimental results validate the effectiveness of the numerical model in simulating velocity profiles and vegetation movement induced by flow.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Linqi Yu, Mustafa Z. Yousif, Meng Zhang, Sergio Hoyas, Ricardo Vinuesa, Hee-Chang Lim
Summary: This study proposes a deep-learning approach to reconstruct three-dimensional high-resolution turbulent flows from spatially limited data and demonstrates its effectiveness through experiments.
Article
Mechanics
Nabil M. Khalifa, Amirsaman Rezaei, Haithem E. Taha
Summary: In this paper, the three-dimensional nature of dynamic stall is investigated through numerical simulations and experimental measurements. The results show that three-dimensional simulations capture the stages of dynamic stall and predict the lift coefficient values more accurately than two-dimensional simulations, with the DES solvers performing better than the URANS ones. Therefore, it is concluded that dynamic stall is intrinsically a three-dimensional phenomenon.
Article
Mechanics
Antoine Michel, Boris Arcen
Summary: Direct numerical simulations are performed to investigate the influence of friction Reynolds number (Re_t) on the translational and angular velocities of inertial, prolate ellipsoids in turbulent channel flow. The quadrant distribution of the turbulent events experienced by the particles remains unchanged with varying Re_t, while subtle modifications occur depending on channel position and particle relaxation time. The statistical moments of the ellipsoids' translational velocity display the same dependence on Re_t as the fluid velocity, and the weak dependence on particle shape observed at low Reynolds numbers persists at higher Re_t. Similarly, the mean and r.m.s. of the particles' angular velocity weakly depend on particle shape and show the same dependence on Re_t as the fluid angular velocity statistics.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Xiaolei Han, Yuyang Zhou, Jiawei Li, Yan Zheng, Akira Rinoshika
Summary: Tomographic particle image velocimetry (PIV) was used to measure and analyze the three-dimensional flow structures and dynamic characteristics behind a fixed-bed barchan dune model. The study found arch-shaped vortex chains and quasi-streamwise vortex structures, and revealed that the arch-shaped vortex system dominates the barchan dune wake.
Article
Mechanics
Alessandro De Rosis, Ruizhi Liu, Alistair Revell
Summary: In this paper, a new simplified lattice Boltzmann method (SLBM) for magnetohydrodynamic flows is proposed, which demonstrates better accuracy and lower virtual memory usage compared to the classical method. The two-stage algorithm of SLBM is replaced by a one-stage procedure, ensuring consistency and ease of implementation. The proposed approach is believed to be an excellent candidate for numerical simulations of two- and three-dimensional magnetohydrodynamic flows.
Article
Multidisciplinary Sciences
Kartik P. Iyer, Sachin S. Bharadwaj, Katepalli R. Sreenivasan
Summary: The study examines the circulation statistics around minimal area loops and finds that they only match those of planar loops circumscribing equivalent areas when normalized by an internal variable such as the standard deviation. This work highlights the previously unknown connection between minimal surfaces and turbulence.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Mechanics
Xiaohan Hu, Imran Hayat, George Ilhwan Park
Summary: This study investigates the predictive capability of three widely used wall models for three-dimensional turbulent boundary layer using wall-modelled large-eddy simulation (WMLES). The results show that while the wall-stress magnitudes predicted by the three wall models are comparable, the PDE non-equilibrium wall model produces a substantially more accurate prediction of the wall-stress direction. The triangular plot of the wall-model solution reveals different capabilities of the wall models in representing variation of flow direction along the wall-normal direction. However, the type of wall model used does not significantly affect the outer LES solution, resulting in nearly identical predictions of mean and turbulent statistics in the outer region.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Livia S. Freire, Marcelo Chamecki
Summary: A stochastic wall model based on the ODT model was developed for LES of smooth and rough channel flows, providing a refined turbulent flow field near the wall. The LES-ODT coupling improved the one-dimensional energy spectra for all three velocity components close to the wall, showing more positive effects in the near-wall spectra than improving the subgrid-scale model. The high computational cost of LES-ODT limits its main use to studies requiring refinement of the near-wall region without the need to refine the entire LES domain.
COMPUTERS & FLUIDS
(2021)
Article
Engineering, Multidisciplinary
J. E. Avalos-Patino, S. J. Neethling, M. D. Piggott
Summary: The challenge in turbulent flow modeling is to balance accuracy and computational cost. Large-eddy simulation (LES) is a widely used method that provides reasonable computational cost compared to direct numerical simulation (DNS). This study aims to develop a LES model that doesn't require user-defined parameters and is suitable for mesh adaptivity with implicit filter. The proposed model shows better performance with lower computational cost compared to the standard Smagorinsky model.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Mechanics
Xander M. de Wit, Adrian van Kan, Alexandros Alexakis
Summary: In this study, direct numerical simulations of thin-layer flow were used to investigate whether the bistable range survives as the domain size and turbulence intensity are increased. The research found that the bistable range grows as the box size and/or Reynolds number Re are increased.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Gen Wu, Le Fang, Jin Zhang
Summary: This paper introduces a new synthetic turbulence method called AEM and applies it to generate inlet conditions in the open-source software code_saturne. By comparing with direct numerical simulation and synthetic eddy method, the ability of AEM to accurately predict turbulent kinetic energy profiles is validated. Parametric analysis is also conducted to discuss the specific effect of each factor.
Article
Engineering, Multidisciplinary
Alessandra Monteleone, Mauro De Marchis, Barbara Milici, Enrico Napoli
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2018)
Article
Computer Science, Interdisciplinary Applications
Mauro De Marchis, Gabriele Freni, Barbara Milici
JOURNAL OF HYDROINFORMATICS
(2018)
Article
Environmental Sciences
Nadia Penna, Mauro De Marchis, Olga B. Canelas, Enrico Napoli, Antonio H. Cardoso, Roberto Gaudio
Article
Engineering, Civil
Mauro De Marchis, Barbara Milici
WATER RESOURCES MANAGEMENT
(2019)
Article
Engineering, Biomedical
Costanza Arico, Marco Sinagra, Robert Nagy, Enrico Napoli, Tullio Tucciarelli
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING
(2020)
Article
Thermodynamics
M. De Marchis, B. Milici, E. Napoli
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2019)
Editorial Material
Computer Science, Interdisciplinary Applications
Mauro De Marchis, Luigi Berardi
JOURNAL OF HYDROINFORMATICS
(2020)
Article
Mechanics
Barbara Milici, Mauro De Marchis, Enrico Napoli
Article
Thermodynamics
Mauro De Marchis, Domenico Saccone, Barbara Milici, Enrico Napoli
FLOW TURBULENCE AND COMBUSTION
(2020)
Article
Environmental Sciences
Paolo Bruno, Gaetano Di Bella, Mauro De Marchis
Article
Environmental Sciences
Federica Bruno, Mauro De Marchis, Barbara Milici, Domenico Saccone, Fabrizio Traina
Summary: Efficient management of water distribution networks is crucial, especially in countries facing water scarcity, and pressure monitoring plays a key role in this. The implementation of IoT technology allows for easy and cost-effective monitoring of water pressure. A smart pressure monitoring system was proposed and tested, showing its ability to effectively manage water pressure in a simple and economical way.
Article
Thermodynamics
Navid Freidoonimehr, Azadeh Jafari, Maziar Arjomandi
Summary: In this study, a high-fidelity flow visualisation technique is used to investigate the resemblance between a turbulent boundary layer generated by different tripping devices in a lab environment and a naturally developed canonical turbulent boundary layer. The study finds that the blockage created by trips is the main factor affecting the turbulence statistics at a certain downstream distance.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2024)
Article
Thermodynamics
Yuning Wang, Alberto Solera-Rico, Carlos Sanmiguel Vila, Ricardo Vinuesa
Summary: This study proposes a method that combines 6-VAEs for modal decomposition and transformer neural networks for temporal-dynamics prediction in the latent space to develop reduced-order models (ROMs) for turbulent flows. The method achieves high reconstruction accuracy and accurate prediction of temporal dynamics.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2024)
Article
Thermodynamics
L. Laguarda, S. Hickel, F. F. J. Schrijer, B. W. van Oudheusden
Summary: Wall-resolved large-eddy simulations were used to investigate the Reynolds number effects in supersonic turbulent boundary layers at Mach 2.0. The study covered a wide range of friction Reynolds numbers and identified trends in various statistics and scaling laws. The size and topology of turbulent structures in the boundary layer were examined, with a focus on the outer-layer motions at high Reynolds numbers. The study also assessed the influence of outer-layer structures on near-wall turbulence and the sensitivity of uniform momentum regions to compressibility.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2024)
Article
Thermodynamics
A. Doehring, T. Kaller, S. J. Schmidt, N. A. Adams
Summary: In this study, well-resolved large-eddy simulations were used to investigate turbulent duct flows with a square cross section. The influence of a modified wall shear stress on the secondary flow was analyzed by artificially modifying the wall shear stress at one of the four walls. The results showed that the modification led to an asymmetrical distribution of the secondary flow source terms, affecting the momentum distribution. Furthermore, the anisotropy of the Reynolds stress tensor, which induces the secondary flow vortices, was significantly affected by the wall shear stress modulation.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2024)