Article
Mechanics
N. Yadav, S. W. Gepner
Summary: Numerical analysis was used to study Couette-Poiseuille (CP) flow in the presence of longitudinal grooves. It was found that the grooves can modify the flow, decrease the phase speed of unstable waves, and reduce the distance required for nonlinear effects.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Mechanics
John P. Koulakis, S. Putterman
Summary: The study investigates the driving force of acoustic field on fluid inhomogeneities, showing that above a certain threshold, the acoustic field can induce instability in the fluid. The locations of acoustic velocity antinodes separate regions of convective stability and instability, and the growth of convective modes with different wavenumbers is influenced by inertia and viscosity.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
D. Bansal, D. Ghosh, S. Sircar
Summary: This study provides a detailed comparison of the linearized analyses of viscoelastic free shear flows under different constitutive equations, showing stability characteristics such as elastic stabilization at higher elasticity numbers and nonmonotonic instability patterns at low to intermediate values of elasticity number for the JS and PTT models. The impact of elasticity, Reynolds number, and viscosity on temporal stability curves of the PTT model is explored, revealing the effects of centerline shear rate on the behavior transition between JS and PTT models. The phase diagrams illustrate regions of inertial turbulence modified by elasticity, elastic turbulence, elastoinertial turbulence, and a stable region for intermediate values of Reynolds and elasticity number.
Article
Mechanics
A. Gergely, Cs. Paizs, R. Toetoes, Z. Neda
Summary: Research on convection-driven fluid columns reveals that increasing the nozzle diameter results in decreased oscillation frequency, while increasing the flow rate leads to higher frequency. Anti-phase synchronization and beating phenomena are observed when helium columns of nearby frequencies are placed close to each other.
Article
Mechanics
S. Heitkam, K. Eckert
Summary: This work demonstrates that anisotropic drainage in sheared foam leads to convective instability in very long foam channels, with liquid accumulating on one side of the channel when a critical liquid fraction is exceeded. Experimental and numerical simulations show that the critical liquid fraction is smaller than previously thought by a factor of five.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
A. Mishra, G. Mamatsashvili, V. Galindo, F. Stefani
Summary: We investigate the convective and absolute forms of azimuthal magnetorotational instability in a cylindrical Taylor-Couette flow with an imposed azimuthal magnetic field. Our results show that the convective AMRI domain is wider than the absolute AMRI domain, but the absolute instability is more relevant and important for magnetic TC flow experiments. The global AMRI in a TC flow of finite height exhibits a butterfly-type structure, with two dominant absolute AMRI modes giving rise to this pattern in a good agreement with linear analysis.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Negar Hosseini, Martin D. Griffith, Justin S. Leontini
Summary: The study shows that when the pitch between two upstream cylinders is large, the downstream wake exhibits a two-row vortex structure, and the shape of the third body has minimal impact on this structure. However, in certain cases, the position of the third body can disrupt the original vortex structure and globally broadcast its presence.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
O. Ruz, E. Castillo, M. Cruchaga
Summary: This study numerically investigates the fluid dynamics and heat transfer of time-dependent flows with shear-thinning behavior over two confined square cylinders in tandem arrangement, showing a transition from laminar to chaotic flow with decreasing power-law index and increasing blockage ratio. Thermal analysis demonstrates an increase in average Nusselt numbers in chaotic flows, and results from the three-dimensional cases confirm those proposed for the two-dimensional case.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Jiakuan Xu, Jianxin Liu, Zhongyu Zhang, Xuesong Wu
Summary: When studying instability of weakly non-parallel flows, it is often desirable to convert temporal growth rates of unstable modes to physically more relevant spatial growth rates. This paper revisits the issue of temporal-spatial transformation and derives more effective transformations for obtaining spatial instability characteristics via temporal stability analysis. These transformations are valid under less restrictive conditions and outperform the existing transformations consistently. They provide accurate results across the entire instability bands, making them useful tools for analyzing spatial instability in various flows.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Mechanics
B. Wang, M. J. Cleary, A. R. Masri
Summary: A new volume of fluid (VoF) model called explicit volume diffusion (EVD) is developed for simulating interfacial flows with turbulence and primary spray atomization. Various closures are proposed to account for sub-volume flux, sub-volume stress, and volume averaged surface tension force. The model is validated through numerical simulations of laminar and turbulent interfacial shear flows, as well as a laboratory-scale airblast spray jet, demonstrating numerical convergence and sensitivity analyses.
Article
Mechanics
D. Bansal, T. Chauhan, S. Sircar
Summary: This study analyzes the linear stability of a displaced Oldroyd-B fluid with the mean flow in a horizontally aligned, square, Hele-Shaw cell to identify the regions of topological transition of the advancing interface. The model considers inertial terms and assumes the interface evolves on a slow timescale. Reasonable agreement is found between the computed data and experimental data. The study reveals the destabilizing and stabilizing effects of inertial terms, finite boundaries, and elasticity on stability in a confined domain.
Article
Mechanics
S. Ceccacci, S. A. W. Calabretto, C. Thomas, J. P. Denier
Summary: A linear stability investigation was conducted on two-dimensional flow in a channel with superhydrophobic walls, finding that the application of slip has a significant stabilizing effect and increases the critical Reynolds number. Both symmetric and asymmetric slip walls were considered, and it was observed that for sufficiently large slip lengths, the flow becomes linearly stable to all disturbances for all wavelengths and Reynolds numbers.
Article
Mechanics
Scott Morgan, Christopher Davies, Christian Thomas
Summary: The study investigates the control of stationary convective instabilities in the rotating disk boundary layer by modulating the disk rotation rate periodically. The addition of a time-periodic modulation stabilizes the flow and raises the critical Reynolds number for the onset of instabilities. Energy analysis shows a reduction in Reynolds stress energy production and an increase in viscous dissipation across the boundary layer with the time-periodic modulation. Comparisons are made with other control techniques such as distributed surface roughness and compliant walls.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mechanics
Shibin Cao, Jiaao Hao, Igor Klioutchnikov, Herbert Olivier, Karl Alexander Heufer, Chih-Yung Wen
Summary: This study investigates the flow characteristics of hypersonic flows over compression ramps with different leading-edge radii using numerical simulations and global stability analysis. The results show that increasing the leading-edge radius can suppress flow separation, reduce aerodynamic heating, and stabilize the flow system.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Mathematics, Applied
A. Alhushaybari, J. Uddin
Summary: The study examines the convective and absolute instability of a viscoelastic liquid jet falling under gravity in an inviscid gas medium. By using numerical methods, regions of instability in parameter space are explored, revealing significant effects of gravity, gas-to-liquid density ratio, Weber number, and Deborah number on instability.
IMA JOURNAL OF APPLIED MATHEMATICS
(2021)
Article
Mechanics
Yi Sui, Peter D. M. Spelt
JOURNAL OF FLUID MECHANICS
(2015)
Article
Mechanics
Zlatko Solomenko, Peter D. M. Spelt, Lennon O. Naraigh, Pascal Alix
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2017)
Article
Computer Science, Interdisciplinary Applications
Zlatko Solomenko, Peter D. M. Spelt, Pascal Alix
JOURNAL OF COMPUTATIONAL PHYSICS
(2017)
Article
Computer Science, Interdisciplinary Applications
M. Capuano, C. Bogey, P. D. M. Spelt
JOURNAL OF COMPUTATIONAL PHYSICS
(2018)
Article
Mechanics
Aurore Loisy, Aurore Naso, Peter D. M. Spelt
JOURNAL OF FLUID MECHANICS
(2018)
Article
Mechanics
A. Titta, M. Le Merrer, F. Detcheverry, P. D. M. Spelt, A. -L. Biance
JOURNAL OF FLUID MECHANICS
(2018)
Article
Mechanics
Lennon O. Naraigh, Peter D. M. Spelt
JOURNAL OF FLUID MECHANICS
(2018)
Review
Mechanics
Yi Sui, Hang Ding, Peter D. M. Spelt
ANNUAL REVIEW OF FLUID MECHANICS, VOL 46
(2014)
Article
Computer Science, Interdisciplinary Applications
Y. Sui, Peter D. M. Spelt
JOURNAL OF COMPUTATIONAL PHYSICS
(2013)
Article
Mechanics
Yi Sui, Peter D. M. Spelt
JOURNAL OF FLUID MECHANICS
(2013)
Article
Mechanics
Lennon O. Naraigh, Prashant Valluri, David M. Scott, Iain Bethune, Peter D. M. Spelt
JOURNAL OF FLUID MECHANICS
(2014)
Article
Physics, Fluids & Plasmas
Z. Wang, Y. Sui, P. D. M. Spelt, W. Wang
Article
Mechanics
Julian F. Scott, Zlatko Solomenko, Peter D. M. Spelt
Summary: This study investigates the behavior of a two-dimensional liquid drop attached to a sinusoidally vibrating wall in the presence of gas, focusing on the damping mechanisms of drop oscillations at small Ohnesorge numbers. The study identifies two distinct damping mechanisms, one from viscous dissipation near the contact lines and characterized by a parameter beta, and the other from the boundary layer at the wall of order Oh(1/2). The research shows that the relative importance of these damping mechanisms depends on the contact angle and beta/Oh(1/2), with cases where one mechanism is dominant or both mechanisms have comparable effects.
INTERNATIONAL JOURNAL OF MULTIPHASE FLOW
(2021)
Article
Mechanics
Aurore Loisy, Aurore Naso, Peter D. M. Spelt
JOURNAL OF FLUID MECHANICS
(2017)