Article
Mechanics
G. L. Richard, F. Couderc, J. P. Vila
Summary: A two-dimensional depth-averaged model is derived for open-channel flows, taking into account turbulence characteristics and shear effects. Numerical simulations show that enstrophy can be used to evaluate the development of the turbulent boundary layer in unsteady flows. The reconstruction of velocity profiles requires parameter modifications different from steady flows, and errors in calculation can occur if steady-state relations are assumed for unsteady flows.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Victor Dupuis, Frederic Y. Moulin, Olivier Eiff
Summary: The experiments were conducted in an open-channel flow with a smooth section and a section consisting of submerged or emergent cubes, resulting in a shear layer with large-scale Kelvin-Helmholtz structures. The analysis of the flow was performed using a double-averaging method, allowing for measurement of the velocity field in a large volume including the interstices between the cubes. The results showed that the loss of momentum towards the rough section had a similar magnitude to the loss through bed friction, and the lateral momentum flux was mainly caused by turbulent shear stress.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
S. Das, R. Balachandar, R. M. Barron
Summary: The characteristics of fully developed smooth open channel flow are studied using two-component planar particle image velocimetry. Flow properties are explored by identifying uniform momentum zones and conditional averaging of flow variables. The difference in flow properties between developing and fully developed flow is evaluated.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Kristin N. Travis, Sarah E. Smith, Laure Vignal, Henda Djeridi, Mickael Bourgoin, Raul Bayoan Cal, Martin Obligado
Summary: This study presents the findings of a wind tunnel experiment investigating the behavior and dynamics of inertial particles in the turbulent wake of a stationary porous disk. The study compares concentrations of poly-disperse water droplets and sub-inertial tracer particles, and analyzes the effects of particle wake interaction on turbulence and particle size distributions in the near and far wake regions.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Christian Schmitz, Peter F. Pelz
Summary: The paper presents an optimal control strategy for maximizing the extracted mechanical power by controlling the tidal flow through a channel connecting two basins with different tidal regimes. The control strategy is determined as a function of the blockage ratio, s, and is based on the energy equation and the relative volume flow. The results provide a physically consistent generalization of previous research and offer advantages in terms of concise analytical solutions and reduced complexity of the control task for turbine arrays.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Jie Yao, Xi Chen, Fazle Hussain
Summary: Well-resolved direct numerical simulations of turbulent open channel flows were performed, and it was found that the flow behavior in the near-wall region is similar to closed channel flows, but differs notably in the outer region. The free surface in open channel flows plays a crucial role in various flow phenomena.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Environmental Sciences
Hasan Zobeyer, Abul B. M. Baki, Saika Nowshin Nowrin
Summary: This study presents experimental results on the mean and turbulence characteristics of flow generated by a pair of cylinders placed in tandem in an open-channel flume, using an acoustic Doppler velocimeter (ADV) to measure the instantaneous three-dimensional velocity components. The downstream cylinder significantly influences the flow development between cylinders, with turbulent peak generally occurring near the end of the recirculation zone in all scenarios.
Article
Mechanics
Matthias Kramer, Daniel Valero
Summary: High-Froude-number flows become self-aerated when turbulence overcomes gravity and surface tension forces. Instead of using single-layer approaches, a new two-state formulation is presented to explain the complete air concentration profile through the weak interaction between turbulent boundary layer and turbulent wavy layer. The proposed flow conceptualization allows for more physically based numerical modeling of turbulent mass diffusion in self-aerated flows.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Krishna S. Kankanwadi, Oliver R. H. Buxton
Summary: The study investigates the physics within the turbulent/turbulent interface (TTI) in the wake of a circular cylinder exposed to free-stream turbulence. The presence of rotational fluid on both sides of the TTI allows the vorticity stretching term to be the dominant actor in enstrophy production. The study also reveals that better 'organised' vorticity on the wake side of the interface leads to the observed enstrophy jump across the TTI.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Energy & Fuels
Bjoern Brenneis, Sergej Gordeev, Sebastian Ruck, Leonid Stoppel, Wolfgang Hering
Summary: Experimental study was conducted on wakes appearing downstream of disturbances on the surface of a water flow in a concave open channel, using an optical measurement system based on laser triangulation. Results showed that the wake depth strongly depended on the size, penetration depth, and circumferential position of the disturbance, yielding a critical wake depth for the liquid lithium target in DONES.
Article
Thermodynamics
Mehedi Hasan Tusar, Palash Kumar Bhowmik, Bodius Salam, Jamal Uddin Ahamed, Jung Kyung Kim
Summary: Helical baffles, wire coils, and rectangular ribs are used as inserts to enhance the turbulence and heat transfer performance of annular fluid flow. Inserts improve heat transfer coefficient and friction factor, with varying degrees of effectiveness depending on factors such as Reynolds number, annulus diameter ratio, and pitch ratio.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Mechanics
A. Apostolidis, J. P. Laval, J. C. Vassilicos
Summary: We found that the Kolmogorov scale-by-scale equilibrium in the intermediate layer of a fully developed turbulent channel flow is only achieved asymptotically around the Taylor length, indicating it is not in an inertial range. Additionally, we analyzed turbulence production and interscale turbulence energy transfer in terms of alignments/anti-alignments of fluctuating velocities, straining/compressive relative motions, forward/inverse interscale transfer/cascade, and homogeneous/non-homogeneous interscale transfer rate contributions. We also proposed leading order scalings for second- and third-order two-point statistics, including the extremum interscale turbulence energy transfer rate and a second-order anisotropic structure function, which acts as a scale-by-scale Reynolds shear stress and determines the scale-by-scale (two-point) turbulence production rate.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Akhil Nekkanti, Sheel Nidhan, Oliver T. Schmidt, Sutanu Sarkar
Summary: This study investigates a turbulent circular disk wake database and identifies the presence of large-scale streaks in the wake, as well as characterizes the lift-up mechanism involved in streak formation. It is the first study to report and characterize large-scale low-frequency streaks and their associated lift-up mechanism in a turbulent wake.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Xiao Hu, Aimee S. Morgans
Summary: This study numerically investigated the three-dimensional flow structures around a high-rise building in different wind conditions using wall-resolved large eddy simulations. The study found that synthetic jet actuation can reduce side-force fluctuations, enhance the downwash flow, and successfully attenuate vortex shedding. These findings could motivate future exploration of experimental active control strategies to mitigate unsteady wind loading.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Civil
Suresh Modalavalasa, Vinay Chembolu, Subashisa Dutta, Vinayak Kulkarni
Summary: The presence of floodplain vegetation can enhance streamwise velocities in a meandering channel. The velocity gradient and turbulent structures at the channel-floodplain interface are influenced by the density of vegetation.
JOURNAL OF HYDROLOGY
(2023)
Article
Environmental Sciences
Oscar Castro-Orgaz, Francisco N. Cantero-Chinchilla
ENVIRONMENTAL FLUID MECHANICS
(2020)
Editorial Material
Environmental Sciences
Hubert Chanson, Fabian Bombardelli, Oscar Castro-Orgaz
ENVIRONMENTAL FLUID MECHANICS
(2020)
Article
Computer Science, Interdisciplinary Applications
Pedro Gamero, Rafael J. Bergillos, Francisco N. Cantero-Chinchilla, Oscar Castro-Orgaz
ENVIRONMENTAL MODELLING & SOFTWARE
(2020)
Review
Environmental Sciences
Oscar Castro-Orgaz, Hubert Chanson
ENVIRONMENTAL FLUID MECHANICS
(2020)
Article
Engineering, Civil
Willi H. Hager, Oscar Castro-Orgaz
JOURNAL OF HYDRAULIC ENGINEERING
(2020)
Article
Engineering, Marine
Francisco N. Cantero-Chinchilla, Rafael J. Bergillos, Oscar Castro-Orgaz
Article
Environmental Sciences
Francisco N. Cantero-Chinchilla, Rafael J. Bergillos, Pedro Gamero, Oscar Castro-Orgaz, Luis Cea, Willi H. Hager
Article
Engineering, Civil
Willi H. Hager, Oscar Castro-Orgaz
Summary: Forum papers are opinion pieces or essays based on facts and speculation on topics relevant to civil engineering and the readers of the journal. The views expressed in these articles do not necessarily represent those of ASCE or the journal's Editorial Board.
JOURNAL OF HYDRAULIC ENGINEERING
(2021)
Editorial Material
Engineering, Civil
Oscar Castro-Orgaz, Hubert Chanson
JOURNAL OF HYDRAULIC RESEARCH
(2021)
Article
Environmental Sciences
Oscar Castro-Orgaz, Hubert Chanson
Summary: This article discusses the undular hydraulic jump in free-surface flow, proposing a depth-averaged model that approximately considers 3D flow effects and comparing the model predictions with experimental results, achieving reasonable agreement. The model does not include flow concentration in the centerline, but analyzes the 3D features at the first wave crest.
ENVIRONMENTAL FLUID MECHANICS
(2022)
Article
Chemistry, Multidisciplinary
Antonino D'Ippolito, Francesco Calomino, Nadia Penna, Subhasish Dey, Roberto Gaudio
Summary: Even though fluid mechanics and numerical studies have made progress, experimental knowledge remains important for studying flow resistance in complex environments. This paper presents the results of experiments and simulations on the drag coefficients in open channels with emergent rigid vegetation. A regression equation was proposed to estimate the drag coefficients based on non-dimensional parameters, and it showed good results for different flow profiles.
APPLIED SCIENCES-BASEL
(2022)
Article
Mechanics
Willi H. Hager, Kolumban Hutter, Oscar Castro-Orgaz
Summary: Fluid viscosity is a key feature affecting fluid flow, with laminar and turbulent flows experiencing different velocities. The letters exchanged between de Saint-Venant and Boussinesq indirectly contributed to the development of turbulence theory and clarified the role of de Saint-Venant in improving the fundamental Navier-Stokes equations. Both turbulence and hydraulic resistance continue to be active areas of research.
COMPTES RENDUS MECANIQUE
(2021)
Article
Mechanics
Willi H. Hager, Kolumban Hutter, Oscar Castro-Orgaz
COMPTES RENDUS MECANIQUE
(2020)
Article
Mechanics
Willi H. Hager, Kolumban Hutter, Oscar Castro-Orgaz
COMPTES RENDUS MECANIQUE
(2020)
Article
Mechanics
Willi H. Hager, Kolumban Hutter, Oscar Castro-Orgaz
COMPTES RENDUS MECANIQUE
(2020)