Article
Mechanics
L. Djenidi, R. A. Antonia
Summary: The study shows that there are differences in the solutions of the Karman-Howarth equation between forced turbulence and decaying turbulence, mainly due to the generation of large-scale motions in forced turbulence. As the Reynolds number increases, the impact of forcing on small scales decreases, allowing the KHEq solutions to agree well with spectrally based solutions at scales unaffected by forcing.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Maurizio Carbone, Michael Wilczek
Summary: Statistically homogeneous flows follow exact kinematic relations, with the Betchov homogeneity constraints being one of the most well-known and extensively used homogeneity relations. These relations have significant implications for the dynamics of fluids and turbulent energy cascade.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
John B. Bell, Andrew Nonaka, Alejandro L. Garcia, Gregory Eyink
Summary: The study investigates the effect of thermal fluctuations in the dissipation range of homogeneous isotropic turbulence using fluctuating hydrodynamics. It confirms theoretical predictions regarding the dominance of these fluctuations in the energy spectrum at length scales comparable to the Kolmogorov length and the presence of Gaussian thermal equipartition in the far-dissipation range.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Qinmin Zheng, Jianchun Wang, Md Mahbub Alam, Bernd R. Noack, Hui Li, Shiyi Chen
Summary: In this study, the transfer of internal energy fluctuation in stationary compressible isotropic turbulence was numerically investigated, where the spectra of velocity, pressure, density, and temperature exhibited scaling laws in the inertial range. The dominance of the solenoidal component over the dilatational component, and the roles of thermal conduction and vibrational relaxation in the dissipation of energy fluctuations were highlighted.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Jin-Han Xie, Shi-Di Huang
Summary: Through simulations of an idealized isotropic convection system, we provide evidence for the existence of Bolgiano-Obukhov (BO) scaling in Rayleigh-Benard convection (RBC) and establish its association with the inverse kinetic energy cascade. We also observe strong intermittent effects in the buoyancy field, but not in the velocity.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Miguel P. Encinar, Javier Jimenez
Summary: The algorithm introduced by Jimenez (J. Fluid Mech., vol. 854, 2018, R1) is used to identify the flow patterns of causal significance in three-dimensional isotropic turbulence. The study finds that the dimensions of the perturbations introduced in the flow are controlled by the kinetic energy content and the enstrophy and dissipation, and affect their significance in the flow. Strain is found to be more efficient than vorticity in propagating the perturbation contents to other regions of the flow. The findings suggest that manipulating strain-dominated vortex clusters is more effective in controlling turbulent flows.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
Kazuhiro Inagaki
Summary: This study investigates the impact of helicity on scale-similar structures of turbulence, revealing that the energy cascade process in the scale-similar range is completely independent of helicity. Additionally, it is found that the helicity cascade is slightly non-local in scales compared to the energy cascade.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
A. Gorbunova, G. Balarac, L. Canet, G. Eyink, V. Rossetto
Summary: The study uses direct numerical simulations to test recent theoretical predictions in a three-dimensional incompressible fluid. Results show agreement with predictions from the Functional Renormalization Group (FRG) and can be explained as a consequence of sweeping. Additionally, there is a crossover in the two-point spatiotemporal correlations of the velocity modulus from Gaussian to exponential decay.
Article
Mechanics
K. Osawa, Y. Minamoto, M. Shimura, M. Tanahashi
Summary: A new technique based on the Voronoi diagram is used to quantify the clustering of fine-scale dissipative vortices. It is found that velocity gradient events are more intense and intermittent with a higher number density of fine-scale vortices. Fine-scale vortex clusters accumulate among stronger vortices rather than accumulating all vortices in the flow.
Article
Meteorology & Atmospheric Sciences
Yuan Li, Reza Sadr
Summary: Summer Shamal, a strong northwesterly wind in the Middle East region, has a broad impact on regional transport and human safety. This study explores the near-surface turbulence characteristics under summer Shamal and compares them with non-Shamal conditions in Qatar coastal region. The results show that Shamal prevents the development of summer sea breezes in the Persian Gulf.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Engineering, Ocean
Mosedul Sarkar, Anjan Samanta, Debarshi Sarkar, Rajib Das, Sankar Sarkar
Summary: This paper presents experimental investigations of flow past two horizontal cylinders. The analysis is based on experimental data captured over a rough-bed with double cylinders of different diameters. General characteristics such as streamwise velocity, Reynolds shear stress, and turbulence intensity profiles are elucidated at different downstream locations. Advanced analysis, such as length scales and turbulent kinetic energy (TKE) budget, are also investigated to show their variations. To accurately determine the TKE dissipation rate, the concept of structure function is employed, and it is verified using Kolmogorov's two-thirds law and the method of power spectra.
MARINE GEORESOURCES & GEOTECHNOLOGY
(2023)
Article
Physics, Fluids & Plasmas
D. O. Mora, M. Bourgoin, P. D. Mininni, M. Obligado
Summary: Through numerical simulations, it was found that clusters of velocity, acceleration, and vorticity null points in turbulence tend to cluster together, with velocity nulls showing the strongest clustering. The denser acceleration and vorticity null points were also observed. The scaling relationships of these null points clusters with Re lambda and turbulence length scales were studied, as well as the preferential concentration of inertial particles with properties resembling Lagrangian acceleration null clustering.
PHYSICAL REVIEW FLUIDS
(2021)
Article
Mathematics, Applied
Feng Liu, Hantao Liu, Hongkai Zhao, Pengfei Lyu
Summary: The inverse energy cascade in homogeneous isotropic turbulence is described using an eigenvalue method, quantitatively capturing the backward energy transfer process and applicable to both isotropic turbulence and resolved velocity fields. This method, based on the product of eigenvalues of the rate-of-strain tensor, is easier to obtain compared to traditional velocity derivative skewness S-k, and has potential for extension to anisotropic turbulence. The presented description aims to inspire future research on modeling the backward energy transfer process and improve the accurate prediction of complex flows.
APPLIED MATHEMATICS AND MECHANICS-ENGLISH EDITION
(2021)
Article
Mechanics
A. Ababaei, B. Rosa, J. Pozorski, L. -P. Wang
Summary: This study investigates the dynamics of inertial particles in turbulence and found that considering lubrication forces and gravity can affect the relative velocities and distribution functions of particles in the near-contact region. However, the effect is minimal away from contact regions, and mass loading significantly impacts collision statistics.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Cameron Verwey, Madjid Birouk
Summary: Estimating the dissipation rate of turbulent kinetic energy in experimental turbulent flows is a challenge. This study rigorously determines epsilon in turbulent helium gas using particle image velocimetry combined with the spatial gradient method, providing comprehensive results of C-epsilon. The results show that C-epsilon eventually falls to around 0.5, but the true asymptotic value remains elusive.
FLOW TURBULENCE AND COMBUSTION
(2022)
Article
Mechanics
Neta-lee Jacobson, Rene van Hout
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2016)
Article
Thermodynamics
R. van Hout, V. Rinsky, Y. G. Grobman
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2018)
Article
Thermodynamics
R. van Hout, V. Rinsky, C. Hershcovich, Y. J. Grobman
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2018)
Article
Physics, Fluids & Plasmas
Rene van Hout, Jerke Eisma, Gerrit E. Elsinga, Jerry Westerweel
PHYSICAL REVIEW FLUIDS
(2018)
Article
Thermodynamics
R. van Hout, V. Rinsky, N. Sasson, C. Hershcovich, M. Tshuva, Y. J. Grobman
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2018)
Article
Engineering, Mechanical
L. Eshbal, D. Kovalev, V Rinsky, D. Greenblatt, R. van Hout
JOURNAL OF FLUIDS AND STRUCTURES
(2019)
Article
Green & Sustainable Science & Technology
A. Amir, R. van Hout
Article
Mechanics
L. Eshbal, V Rinsky, T. David, D. Greenblatt, R. van Hout
JOURNAL OF FLUID MECHANICS
(2019)
Article
Thermodynamics
M. Raizner, V. Rinsky, G. Grossman, R. van Hout
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2019)
Article
Physics, Fluids & Plasmas
Sofia Kuperman, Lilach Sabban, Rene van Hout
PHYSICAL REVIEW FLUIDS
(2019)
Article
Thermodynamics
M. Raizner, V. Rinsky, G. Grossman, R. van Hout
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2019)
Article
Thermodynamics
M. Raizner, R. van Hout
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2020)
Review
Physics, Fluids & Plasmas
Rene van Hout, Sudharson Murugan, Abhijit Mitra, Beni Cukurel
Summary: This review article focuses on the near-field flow characteristics of coaxial circular jets, discussing the impact of velocity ratios and nozzle geometry on the flow, as well as the presence of shear and wake instabilities. It also explores different states of coaxial jets in the near-field and their potential for specific heat and mass transfer applications.
Article
Mechanics
L. Sabban, A. Cohen, R. van Hout
JOURNAL OF FLUID MECHANICS
(2017)
Proceedings Paper
Mechanics
Rene van Hout
PARTICLES IN WALL-BOUNDED TURBULENT FLOWS: DEPOSITION, RE-SUSPENSION AND AGGLOMERATION
(2017)
Article
Engineering, Chemical
Francisco J. Higuera, Juan Fernandez de la Mora
Summary: This study investigates a particle condensation device that uses cold and warm humid air streams to achieve water vapor condensation. Compared to existing water condensation particle counters, this configuration offers advantages such as variable saturation ratio, accelerated penetration of water vapor, and a relatively uniform saturation field.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Brijal Prajapati, Vishal Dharaiya, Manoranjan Sahu, Chandra Venkatraman, Pratim Biswas, Kajal Yadav, Delwin Pullokaran, Ramya Sunder Raman, Ruqia Bhat, Tanveer Ahmad Najar, Arshid Jehangir
Summary: This study evaluated the performance of a low-cost particulate matter sensor and proposed a physics-based calibration method. The results showed that the physics-based calibration approach performed better compared to statistical models at both observation sites.
JOURNAL OF AEROSOL SCIENCE
(2024)
Correction
Engineering, Chemical
N. Searle, K. Kaur, K. Kelly
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Tianyu Cen, Laura Torrent, Andrea Testino, Christian Ludwig
Summary: In this study, a hyphenated setup consisting of a rotating disk diluter (RDD) with spICP-MS (RDDspICP-MS) was used for online sampling and characterization of metallic nanoparticles (NPs) in ambient pressure aerosols. The RDD allowed for constant flow rate sampling of aerosols and adjusting the dilution ratio for different particle number concentrations (PNCs). The feasibility of this setup was tested with different sizes of AuNPs in argon-based and air-based aerosols, and the results showed a lower limit of detection for number concentration. The capability of the setup to accurately investigate multi-modal samples and the interference of ionic species was also demonstrated.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
A. Valenzuela, E. Bazo, R. A. Rica, L. Alados-Arboledas, F. J. Olmo-Reyes
Summary: This article introduces a method to measure the extinction cross section of levitated particles using an electrodynamic trap and double-cavity ring down spectroscopy technique, and demonstrates the potential of this method in 1,2,6-hexanetriol particles through simulations and experiments. Unlike traditional methods, this technique provides crucial information about the extinction cross section of sodium chloride particles during dehydration and hydration processes.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Shadi Yaqoubi, Mohaddese Sokuti, Sahand Mazloum-Ravasan, Kofi Asare-Addo, Hamed Hamishehkar, Ali Nokhodchi
Summary: In this study, a modified version of ultrasonic spray pyrolysis was used to prepare salbutamol sulfate dry powder. The engineered particles showed suitable characteristics for effective drug delivery to the lungs and demonstrated acceptable aerosolization performance. This newly introduced method appears to be capable of producing dry powder formulations of different drugs without the need for surfactants or stabilizers.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Ashley L. Nord, Patrice Dosset, Pierre Slangen, Manouk Abkarian
Summary: Phonation has been found to be a potent transmission route for the COVID-19 virus. To control transmission, it is important to measure the amount of aerosols produced by speech. Researchers used digital in-line holography to overcome experimental challenges and successfully imaged the formation and deformation of saliva filaments in the mouth during speech, as well as the resulting aerosolized droplets.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Yating Wang, Yiyang Zhang, Zhu Fang, Xinxin Wu
Summary: The research investigates the energy dissipation in particle-wall collision with roughness using the finite element method. The results show that the presence of surface roughness leads to lower viscoelastic dissipation and higher restitution coefficient compared to a smooth surface. The collision time is identified as a key factor in predicting the energy dissipation.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Shaamrit Balendra, Akshay Kale, Julie Pongetti, Mohsen Kazemimanesh, Molly Haugen, Lee Weller, Adam Boies
Summary: The measurement of airborne particles is important for detecting and characterising air pollution, emissions, fire detection, occupational and climate impacts. However, current optical particle counters (OPCs) cannot measure ultrafine particles. This study explores the limitations of miniaturising a condensation particle counter (CPC) growth chamber and provides a toolkit for optimising the design of miniaturised CPC-GCs.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Markus Snellman, Namsoon Eom, Maria E. Messing, Knut Deppert, Chris Hogan
Summary: Segregated bimetallic nanoparticles, such as core-shell nanoparticles, have attracted widespread interest in various fields like biomedicine, catalysis, and optoelectronics. Aerosol technology provides an optimal platform for controlling the size, structure, and composition of nanoparticles, which are crucial parameters for tuning the material performance for specific applications. In this study, researchers developed a novel evaporator design that allows on-line coating of core particles with a shell directly in the gas phase. By utilizing a local heater, the researchers were able to decouple the heating process of the evaporating material from the aerosol particles, thereby limiting core-shell alloying. The resulting core-shell particle formation with controllable shell thickness was demonstrated using evaporation of zinc onto core particles of gold, tin, and bismuth. Simple models were also discussed to explain the observed growth process inside the evaporator and the formation of the shell.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Kentaro Misawa, Yuto Kasai
Summary: In this study, the laser-induced fluorescence technique was used to observe scattered and fluorescent signals from fluorescent polystyrene latex particles. The ratio of fluorescence to scattered signal intensities was found to be almost equal for particles of the same size, allowing for the separate observation of mixed-size fluorescent particles. Relative fluorescence intensities were obtained by incorporating ratios of fluorescence to scattered signal and relative scattered signal intensities.
JOURNAL OF AEROSOL SCIENCE
(2024)
Article
Engineering, Chemical
Sripriya Nannu Shankar, William B. Vass, John A. Lednicky, Tracey Logan, Rebeccah L. Messcher, Arantzazu Eiguren-Fernandez, Stavros Amanatidis, Tara Sabo-Attwood, Chang-Yu Wu
Summary: This study introduces a testing system that allows for direct exposure of aerosolized viruses onto host cells. By collecting particles of different sizes and analyzing them, researchers obtained information on the concentration and viability of the virus at different particle sizes.
JOURNAL OF AEROSOL SCIENCE
(2024)