Article
Mechanics
Manas Ranjan Behera, Anirvan Dasgupta, Sudipto Chakraborty
Summary: The evolution of a vortex ring generated by drop impinging on a liquid pool was studied experimentally, numerically, and analytically. A novel analytical model for a finite vortex core was developed and validated with experimental results. The controlling parameters governing the viscous diffusion-driven evolution of the vortex ring were uncovered. The study provided valuable insights into the formation and viscous diffusion process of the vortex ring through a combination of experimental, numerical, and analytical approaches.
Article
Mechanics
S. Advaith, K. T. Aswathi, Saptarshi Basu
Summary: This paper quantitatively investigates the topology and formation mechanisms of vortex rings under externally modulated parameters, predicting vortex characteristics and validating them through experiments. The study shows that external parameters can be collapsed into a universal variable, providing insights into vortex roll-up characteristics and energy distribution variations.
EUROPEAN JOURNAL OF MECHANICS B-FLUIDS
(2022)
Article
Mechanics
Yuan-Heng Zhang, Huan-Feng Duan, Xu-Feng Yan, Alessandro Stocchino
Summary: This paper presents an experimental study on the impact of variable solid volume fractions and aspect ratios on the flow behavior and wake structure of a centre-channel rectangular porous patch. The study establishes the importance of aspect ratio in wake vortex generation. By elongating the patch, a vortex street can be generated due to the promotion of transverse velocity gradient in the wake region. The paper also proposes non-dimensional threshold maps to express the combined effects of solid volume fraction and aspect ratio on the initiation of the wake vortex street.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Engineering, Civil
Ruwei Ma, Qiang Zhou, Peiyuan Wang, Yang Yang, Mingshui Li, Shuyang Cao
Summary: This study investigated the vortex-induced force on an oscillating rectangular cylinder encountering a sinusoidal streamwise gust through wind tunnel tests and CFD simulations. The results show that the Karman-vortex-induced force almost disappeared in the sinusoidal gust, while the motion-induced force remained almost unchanged. The CFD simulations revealed that the flow structure around the rectangular cylinder is sensitive to the oncoming flow condition, suppressing alternative vortex shedding in the near wake.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2021)
Article
Engineering, Marine
Bin Liu, Renjie Jiang
Summary: The vortex-induced vibrations (VIV) of an elastically mounted rectangular cylinder with one degree of freedom in a viscous incompressible uniform flow were studied using the lattice Boltzmann method. The results showed that the side ratio and mass ratio have significant influences on the behaviors of the fluids and structures. The resonance can be extensively excited and its region expands with decreasing side ratio and mass ratio. Three distinct vortex wake modes were observed. Mechanistic analysis indicated that the shift of oscillation frequency was induced by the competition between the wake mode and structure mode, and large-amplitude vibrations in the resonance region were caused by power transfer between the fluids and structures. The excitation of wake mode was associated with the cylinder shape and response amplitude, and the process of vortex formation had significant influences on the cylinder motion.
Article
Mechanics
A. Chiarini, M. Quadrio, F. Auteri
Summary: This study investigates the shedding phenomenon and interaction between vortices in elongated rectangular cylinders at moderate Reynolds numbers. It is found that with increasing aspect ratio, two different flow behaviors are observed, and there is hysteresis in the Strouhal number near certain aspect ratios.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
Herve Henry
Summary: The effect of buoyant forces on viscous coarsening is studied numerically. It is found that buoyant forces induce a vertical flow scaling with the Stokes velocity at any time. Below a certain threshold, this does not cause notable changes in the morphology of the coarsening microstructure. However, above the threshold, the pattern evolves towards a quasi 2D structure and coarsening ceases. The characteristic length is shown to scale with the square root of gamma/(g delta rho), where gamma is the surface tension and delta rho is the mass density difference between the phases.
Article
Engineering, Marine
Guanghao Chen, Md. Mahbub Alam, Yu Zhou, Chunning Ji, Hongjun Zhu
Summary: This study investigates vortex-induced vibrations of an elastically supported circular cylinder under wall interference. It is found that a smaller wall-cylinder gap height ratio increases the added mass, reduces the maximum vibration amplitude, and shortens the vibration range, while enhancing the quality factor of the vibration. Decreasing the gap height ratio significantly impacts the flow structure and vortex shedding modes.
Article
Engineering, Mechanical
Chaoqun Wang, Qing Wen, Shuai Zhou, Xugang Hua, Zhiwen Huang, Zhengqing Chen
Summary: A series of wind tunnel tests were conducted to examine the effects of aspect ratio and end condition on the vortex-induced vibration of a rectangular cylinder. The results indicated that the aspect ratio had a significant impact on the vibration amplitudes, while the end condition and vibration had little effect on the length of the interference region.
JOURNAL OF FLUIDS AND STRUCTURES
(2022)
Article
Nuclear Science & Technology
Botao Zhang, Shengjie Gong, Shichang Dong, Zhenqin Xiong, Zhen Zhang
Summary: The study examined the vortex shedding behavior of a spacer grid in a confined rectangular channel through experiments and numerical simulations. The results demonstrated good agreement between numerical and experimental data, showing that the Reynolds number based on plate thickness and the dimensionless width of the channel could influence the vortex shedding modes. Higher Reynolds numbers or lower channel width to plate thickness ratios resulted in stronger leading edge vortices.
PROGRESS IN NUCLEAR ENERGY
(2021)
Article
Multidisciplinary Sciences
Nehad Ali Shah, Hussam Alrabaiah, Dumitru Vieru, Se-Jin Yook
Summary: This study investigates the unsteady, magneto-hydrodynamic generalized Couette flows of two immiscible fluids in a rectangular channel under the influence of an inclined magnetic field and an axial electric field. The velocity, induced magnetic, and temperature fields are determined using the Laplace transform method and a numerical scheme based on finite differences. The study also examines the evolution of fluid velocity, induced magnetic field, and viscous dissipation in both flow regions.
SCIENTIFIC REPORTS
(2022)
Article
Biochemistry & Molecular Biology
Albert E. Lisitsa, Lev A. Sukovatyi, Sergey Bartsev, Anna A. Deeva, Valentina A. Kratasyuk, Elena Nemtseva
Summary: The viscosity of the media influences the rate constants of the separate stages of the bacterial bioluminescent reaction. Glycerol and sucrose solutions affect the formation of enzyme intermediates and the binding of substrates. Sucrose solutions promote enzyme catalytic constant and exclusion from the catalytic gorge of luciferase, leading to the formation of active site structure favorable for the catalysis.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Thermodynamics
Tofigh Moradi, Hamidreza Shahbazian, Mostafa Hoseinalipour, Bengt Sunden
Summary: An experimental and numerical study was conducted to analyze the effects of rib configurations on heat transfer in U-turn rotating rectangular channels. A new model of wavy ribs was studied and compared with traditional rectangular cross-section ribs. Computational fluid dynamics (CFD) with the k-omega SST turbulence model were used to investigate the flow structure, thermal performance, turbulent kinetic energy, and Nusselt numbers. The results showed that the thermal performance of wavy ribs was 22.1%-28.7% higher than rectangular cross-section ribs.
APPLIED THERMAL ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
S. Nell, F. Yang, Z. Evenson, A. Meyer
Summary: The study shows that in the liquid Ni66.7B33.3, the product of viscosity and self-diffusion coefficient remains relatively constant over the entire temperature range, whereas in the liquid Ge66.7Ni33.3, this product increases with temperature, indicating a better agreement with an activated process. The two liquid materials exhibit different temperature dependencies.
Article
Thermodynamics
Y. Amini, S. E. Habibi
Summary: In this study, the hydrothermal characteristics of heat sinks with multiple vortex generators (VGs) were investigated. The use of flexible splitters on the VGs significantly improved heat transfer capability and hydrothermal performance. By selecting proper configurations, the rejected heat can be increased by 190% at the expense of a 10% decrease in total hydrothermal efficiency.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Mechanics
Abbas Ghasemi, Burak Ahmet Tuna, Xianguo Li
JOURNAL OF FLUID MECHANICS
(2018)
Article
Engineering, Mechanical
Burak A. Tuna, Serhiy Yarusevych, Xianguo Li, Yi Ren, Fanghui Shi
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2019)
Article
Mechanics
Abbas Ghasemi, Burak Ahmet Tuna, Xianguo Li
JOURNAL OF FLUID MECHANICS
(2019)
Article
Engineering, Aerospace
Burak A. Tuna, John W. Kurelek, Serhiy Yarusevych
Article
Engineering, Mechanical
Stephen James Gill, Burak A. Tuna, Serhiy Yarusevych, Xianguo Li, Fanghui Shi
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2020)
Article
Thermodynamics
S. Pieris, B. A. Tuna, S. Yarusevych, S. D. Peterson
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2020)
Article
Thermodynamics
Abbas Ghasemi, Xianguo Li, Zekai Hong, Sangsig Yun
ENERGY CONVERSION AND MANAGEMENT
(2020)
Article
Engineering, Aerospace
John W. Kurelek, Burak A. Tuna, Serhiy Yarusevych, Marios Kotsonis
Summary: Experimental assessment of three-dimensional flow development over a NACA 0018 airfoil under specific conditions reveals the formation of strongly two-dimensional separation bubbles in both natural and weakly excited cases. Analysis shows the formation of spanwise-oriented and strongly two-dimensional shear-layer vortices in the separation bubble upstream, with spanwise undulations in the vortex filaments leading to the development of hairpinlike structures downstream.
Article
Energy & Fuels
Amir Panahi, Abbas Ghasemi, Xianguo Li
Summary: This study investigates the interaction of particulate matter (PM) in the gas stream and their capture efficiency by fibrous structure of gas diffusion layers (GDLs) at different levels of relative humidity (RH) and particle sizes. It is found that high humidity levels result in higher diameter and lower density of PM, leading to lower air density and particle bounce. The increase in humidity level decreases capture efficiency for small particles but increases it for large particles, highlighting the importance of installing a filter for removing large particles in the reactant gas supply line to prevent PM accumulation in GDL structure.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Thermodynamics
Xueqing Zhang, Burak A. Tuna, Serhiy Yarusevych, Sean D. Peterson
Summary: The study investigates flow development over isolated, surface-mounted, droplet-inspired three-dimensional obstacles submerged in a laminar boundary layer at a Reynolds number of Re-h = 2070 using particle image velocimetry. Three different geometries are considered, each producing various vortex systems and wake formations downstream of the obstacles. Shear layer vortices and interactions between different vortices play a key role in the flow dynamics, with the spherical cap providing a reasonable first order approximation of a sessile droplet. The runback model exhibits unique characteristics with more complete merging of shear layer vortices and a narrower near-field wake compared to the other models, indicating less disruption to the incoming boundary layer flow.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2021)
Article
Engineering, Aerospace
S. Gildersleeve, B. A. Tuna, M. Amitay