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The shape of a microchannel is usually affected by a significant uncertainty due to the small size of the cross-section, comparable with the typical wall-roughness length scale. Such an uncertainty is present at any scale, but it is…

Fluid Dynamics · Physics 2024-06-18 A. Barletta , M. Celli , L. A. Sphaier , P. V. Brandao , S. Lazzari , E. Ghedini

The shape of a microchannel cross-section is usually affected by a significant uncertainty due to the small hydraulic diameter. Such an uncertainty is indeed present at any scale, but is amplified in smaller scales, becoming significantly…

Fluid Dynamics · Physics 2024-06-26 L. A. Sphaier , A. Barletta , M. Celli , P. V. Brandao , S. Lazzari , E. Ghedini

Heat and momentum transfer in wall-bounded turbulent flow, coupled with the effects of wall-roughness, is one of the outstanding questions in turbulence research. In the standard Rayleigh-B\'enard problem for natural thermal convection, it…

Fluid Dynamics · Physics 2019-07-05 Michael MacDonald , Nicholas Hutchins , Detlef Lohse , Daniel Chung

We study numerically the dependence of heat transport on the maximum velocity and shear rate of physical circulating flows, which are prescribed to have the key characteristics of the large-scale mean flow observed in turbulent convection.…

Chaotic Dynamics · Physics 2009-11-07 Emily S. C. Ching , K. M. Pang

We studied flow organization and heat transfer properties in mixed turbulent convection within Poiseuille-Rayleigh-B\'enard channels subjected to temporally modulated sinusoidal wall temperatures. Three-dimensional direct numerical…

Fluid Dynamics · Physics 2025-03-12 Ao Xu , Rui-Qi Li , Heng-Dong Xi

Compact and small-scale heat exchangers can handle high heat dissipation rates due to their large surface area to volume ratios. Applications involving high heat dissipation rates include, but are not limited to, compact microelectronic…

Fluid Dynamics · Physics 2021-06-23 Mahyar Pourghasemi , Nima Fathi , Sal Rodriguez

In this study, we performed highly resolved large-eddy simulations (LES) to investigate the influence of variable properties on the forced turbulent convection in a channel. The constant heat flux boundary condition permits wall temperature…

Fluid Dynamics · Physics 2023-01-11 Himani Garg , Lei Wang

Direct numerical simulations were performed to characterize fully developed supersonic turbulent channel flows over isothermal rough walls. The effect of roughness was incorporated using a level-set/volume-of-fluid immersed boundary method.…

Direct Numerical Simulations are used to solve turbulent flow and heat transfer over a variety of rough walls in a channel. The wall geometries are exactly resolved in the simulations. The aim is to understand the effect of roughness…

Fluid Dynamics · Physics 2018-06-25 Pourya Forooghi , Matthias Stripf , Bettina Frohnapfel

In this paper, we investigate the effect of boundary surface roughness on numerical simulations of incompressible fluid flow past a cylinder in two and three spatial dimensions furnished with slip boundary conditions. The governing…

Fluid Dynamics · Physics 2025-11-05 Matthias Maier , Peter Munch , Murtazo Nazarov

Mesoscale convection covers an intermediate scale range between small-scale turbulence and the global organization of the convection flow. It is often characterized by an order of the convection patterns despite very high Rayleigh numbers…

Direct numerical simulations of turbulent channels with rough walls are conducted in the transitionally rough regime. The effect that roughness produces on the overlying turbulence is studied using a modified triple decomposition of the…

Fluid Dynamics · Physics 2020-07-21 Nabil Abderrahaman-Elena , Chris T. Fairhall , Ricardo García-Mayoral

A comprehensive study of the effect of wall heating or cooling on the linear, transient and secondary growth of instability in channel flow is conducted. The effect of viscosity stratification, heat diffusivity and of buoyancy are estimated…

Fluid Dynamics · Physics 2021-01-29 A. Sameen , Rama Govindarajan

This study analyzes the behavior of a differentially heated channel flow by means of a direct numerical simulations (DNS) with variable thermophysical properties under low-speed conditions focusing on the impact of the temperature gradient…

Fluid Dynamics · Physics 2025-06-30 Marina Garcia-Berenguer , Lucas Gasparino , Oriol Lehmkuhl , Ivette Rodriguez

The dynamics and rheology of a vesicle confined in a channel under shear flow are studied at finite temperature. The effect of finite temperature on vesicle motion and system viscosity is investigated. A two-dimensional numerical model,…

Soft Condensed Matter · Physics 2022-10-04 A. Lamura

In this paper, we study the asymptotic behavior of the thermomicropolar fluid flow through a thin channel with rough boundary. The flow is governed by the prescribed pressure drop between the channel's ends and the heat exchange through the…

Analysis of PDEs · Mathematics 2025-12-22 Igor Pažanin , Francisco J. Suárez-Grau

Using event-driven molecular dynamics simulations, we quantify how the self diffusivity of confined hard-sphere fluids depends on the nature of the confining boundaries. We explore systems with featureless confining boundaries that treat…

Soft Condensed Matter · Physics 2015-05-30 William P. Krekelberg , Vincent K. Shen , Jeffrey R. Errington , Thomas M. Truskett

We demonstrate the ability to experimentally measure fluctuations of the convective heat transfer coefficient at the wall in a turbulent boundary layer. For this, we measure two-dimensional fields of wall-temperature fluctuations beneath a…

Fluid Dynamics · Physics 2025-02-04 Firoozeh Foroozan , Andrea Ianiro , Stefano Discetti , Woutijn J. Baars

The problem of convective instability onset in a horizontal porous channel is explored. The channel's impermeable walls are heated with asymmetric thermal conditions modelled through unequal, but uniform, wall heat fluxes. A stationary…

Fluid Dynamics · Physics 2025-08-22 A. Barletta , M. Celli , P. V. Brandão

The influence of near-wall density and viscosity gradients on near-wall turbulence in a channel are studied by means of Direct Numerical Simulation (DNS) of the low-Mach number approximation of the Navier--Stokes equations. Different…

Fluid Dynamics · Physics 2023-02-17 Ashish Patel , Bendiks Jan Boersma , Rene Pecnik
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