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We numerically investigate turbulent Rayleigh-B\'enard convection with gas bubbles attached to the hot plate, mimicking a core feature in electrolysis, catalysis, or boiling. The existence of bubbles on the plate reduces the global heat…

Fluid Dynamics · Physics 2022-08-17 Hao-Ran Liu , Kai Leong Chong , Rui Yang , Roberto Verzicco , Detlef Lohse

We studied the transport and deposition behaviour of point particles in Rayleigh-B\'enard convection cells subjected to Couette-type wall shear. Direct numerical simulations (DNSs) are performed for Rayleigh number ($Ra$) in the range $10^7…

Fluid Dynamics · Physics 2024-11-20 Ao Xu , Ben-Rui Xu , Heng-Dong Xi

Turbulent-laminar banded patterns in plane Poiseuille flow are studied via direct numerical simulations in a tilted and translating computational domain using a parallel version of the pseudospectral code Channelflow. 3D visualizations via…

In this dissertation two-dimensional buoyancy-driven flows are investigated. While usually the Navier-Stokes equations are equipped with no-slip boundary conditions here we focus on the Navier-slip conditions that, depending on the system…

Analysis of PDEs · Mathematics 2024-09-25 Fabian Bleitner

The buoyancy-induced parallel flow in a vertical cylindrical porous layer is analysed. A radial thermal gradient caused by a uniformly distributed heat source is assumed to induce the buoyant flow. The layer boundaries are modelled as…

Fluid Dynamics · Physics 2023-02-03 A. Barletta , D. A. S. Rees , B. Pulvirenti

We report an experimental study of the properties of the velocity boundary layer in turbulent Rayleigh-B\'{e}nard convection in a cylindrical cell. The measurements were made at Rayleigh numbers $Ra$ in the range…

Fluid Dynamics · Physics 2015-06-11 Ping Wei , Ke-Qing Xia

We numerically investigate turbulent Rayleigh-B\'enard convection within two immiscible fluid layers, aiming to understand how the layer thickness and fluid properties affect the heat transfer (characterized by the Nusselt number $Nu$) in…

Fluid Dynamics · Physics 2022-05-24 Hao-Ran Liu , Kai Leong Chong , Rui Yang , Roberto Verzicco , Detlef Lohse

The objective of this work is to investigate linear modal and algebraic instability in Poiseuille flows with fluids close to their vapour-liquid critical point. Close to this critical point, the ideal gas assumption does not hold and large…

Fluid Dynamics · Physics 2020-05-14 Jie Ren , Song Fu , Rene Pecnik

Poiseuille flow in cylindrical and planar geometries with a simplified, pseudoplastic (shear thinning) rheology characterized by constant viscosity plateaus above and below a transition strain rate is considered. Analytical, steady state…

Fluid Dynamics · Physics 2024-07-26 Chris Reese

We show that viscoelastic plane Poiseuille flow becomes linearly unstable in the absence of inertia, in the limit of high elasticities, for ultra-dilute polymer solutions. While inertialess elastic instabilities have been predicted for…

Fluid Dynamics · Physics 2021-09-29 Mohammad Khalid , V. Shankar , Ganesh Subramanian

This study presents an experimental dataset documenting the evolution of a turbulent boundary layer downstream of a rough-to-smooth surface transition. To investigate the effect of upstream flow conditions, two groups of experiments are…

We investigate the large-scale circulation (LSC) of turbulent Rayleigh-B\'enard convection in a large box of aspect ratio $\Gamma =32$ for Rayleigh numbers up to $Ra=10^9$ and at a fixed Prandtl number $Pr=1$. A conditional averaging…

Linear stability of inviscid, parallel, and stably stratified shear flow is studied under the assumption of smooth strictly monotonic profiles of shear flow and density, so that the local Richardson number is positive everywhere. The…

Fluid Dynamics · Physics 2016-05-04 Makoto Hirota , Philip J. Morrison

We perform a two-dimensional numerical study on the thermal effect of porous media on global heat transport and flow structure in Rayleigh-B\'enard (RB) convection, focusing on the role of thermal conductivity $\lambda$ of porous media,…

Fluid Dynamics · Physics 2023-04-17 Jun Zhong , Shuang Liu , Chao Sun

In this paper, the physics of flow instability and turbulent transition in shear flows is studied by analyzing the energy variation of fluid particles under the interaction of base flow with a disturbance. For the first time, a model…

Fluid Dynamics · Physics 2018-06-20 Hua-Shu Dou

The Brownian motion of a particle in a harmonic potential, which is simultaneously exposed either to a linear shear flow or to a plane Poiseuille flow is investigated. In the shear plane of both flows the probability distribution of the…

Fluid Dynamics · Physics 2010-04-22 Lukas Holzer , Jochen Bammert , Roland Rzehak , Walter Zimmermann

We study the effects of externally imposed shear and buoyancy driven flows on the stability of a solid-liquid interface. By reanalyzing the data of Gilpin \emph{et al.} [\emph{J. Fluid Mech.}, {\bf 99}(3), 619 (1980)] we show that the…

Fluid Dynamics · Physics 2020-07-06 Srikanth Toppaladoddi , John S. Wettlaufer

This study considers the linear stability of Poiseuille-Rayleigh-B\'enard flows, subjected to a transverse magnetic field to understand the instabilities that arise from the complex interaction between the effects of shear, thermal…

Fluid Dynamics · Physics 2017-09-01 Tony Vo , Gregory J. Sheard , Alban Pothérat

The equations of motion describing buoyant fluids are often simplified using a set of approximations proposed by J. Boussinesq one century ago. To resume, they consist in assuming constant fluid properties, incompressibility and…

Classical Physics · Physics 2007-10-19 Philippe-Emmanuel P. -E. Roche

We investigate the effect of inertial particles on Rayleigh-B\'enard convection using weakly nonlinear stability analysis. In the presence of nonlinear effects, we study the limiting value of growth of instabilities by deriving a cubic…

Fluid Dynamics · Physics 2025-03-20 Thota Srinivas , Gaurav Tomar