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Nudging is an important data assimilation technique where partial field measurements are used to control the evolution of a dynamical system and/or to reconstruct the entire phase-space configuration of the supplied flow. Here, we apply it…

Fluid Dynamics · Physics 2020-02-12 P. Clark Di Leoni , A. Mazzino , L. Biferale

Rayleigh-B\'enard convection in the turbulent regime is studied using statistical methods. Exact evolution equations for the probability density function of temperature and velocity are derived from first principles within the framework of…

Fluid Dynamics · Physics 2011-03-04 J. Lülff , M. Wilczek , R. Friedrich

Inferring physical parameters of turbulent flows by assimilation of data measurements is an open challenge with key applications in meteorology, climate modeling and astrophysics. Up to now, spectral nudging was applied for empirical…

Fluid Dynamics · Physics 2018-10-29 P. Clark Di Leoni , A. Mazzino , L. Biferale

Rayleigh-B\'enard convection, i.e. the flow of a fluid between two parallel plates that is driven by a temperature gradient, is an idealised setup to study thermal convection. Of special interest are the statistics of the turbulent…

We introduce a continuous (downscaling) data assimilation algorithm for the 2D B\'enard convection problem using vorticity or local circulation measurements only. In this algorithm, a nudging term is added to the vorticity equation to…

Analysis of PDEs · Mathematics 2017-09-11 Aseel Farhat , Hans Johnston , Michael S. Jolly , Edriss S. Titi

In this paper we propose a continuous data assimilation (downscaling) algorithm for the B\'enard convection in porous media using only coarse mesh measurements of the temperature. In this algorithm, we incorporate the observables as a…

Analysis of PDEs · Mathematics 2015-10-12 Aseel Farhat , Evelyn Lunasin , Edriss S. Titi

A data-driven turbulence model for coarse-grained numerical simulations of two-dimensional Rayleigh-B\'enard convection is proposed. The model starts from high-fidelity data and is based on adjusting the Fourier coefficients of the…

Fluid Dynamics · Physics 2024-02-08 Sagy Ephrati , Paolo Cifani , Bernard Geurts

We have developed novel instrumentation for making Lagrangian measurements of temperature in diverse fluid flows. A small neutrally buoyant capsule is equipped with on-board electronics which measure temperature and transmit the data via a…

Fluid Dynamics · Physics 2011-12-06 Woodrow L. Shew , Yoann Gasteuil , Mathieu Gibert , Pascal Metz , Jean-Francois Pinton

We investigate numerically the statistical properties of the large scale flow in Rayleigh--B\'enard convection. By using an external random perturbation on the temperature field, we were able to decrease the effective Prandtl number of the…

Chaotic Dynamics · Physics 2007-05-23 Roberto Benzi , Roberto Verzicco

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

Employing numerical simulations, we provide an accurate insight into the of heat transfer mechanisms in the Rayleigh-B\'enard convection of concentrated emulsions with finite-size droplets. We focus on the unsteady dynamics characterizing…

Fluid Dynamics · Physics 2024-02-14 Francesca Pelusi , Stefano Ascione , Mauro Sbragaglia , Massimo Bernaschi

We have developed a small, neutrally buoyant, wireless temperature sensor. Using a camera for optical tracking, we obtain simultaneous measurements of position and temperature of the sensor as it is carried along by the flow in…

This work applies a continuous data assimilation scheme---a particular framework for reconciling sparse and potentially noisy observations to a mathematical model---to Rayleigh-B\'enard convection at infinite or large Prandtl numbers using…

Fluid Dynamics · Physics 2022-04-28 A. Farhat , N. E. Glatt-Holtz , V. R. Martinez , S. A. McQuarrie , J. P. Whitehead

The non-hydrostatic, quasigeostrophic approximation for rapidly rotating Rayleigh-B\'enard convection admits a class of exact `single mode' solutions. These solutions correspond to steady laminar convection with a separable structure…

Fluid Dynamics · Physics 2015-06-03 Ian Grooms

This study explores heat and turbulent modulation in three-dimensional multiphase Rayleigh-B\'enard convection using direct numerical simulations. Two immiscible fluids with identical reference density undergo systematic variations in…

Fluid Dynamics · Physics 2024-08-26 Abbas Moradi Bilondi , Nicolò Scapin , Luca Brandt , Parisa Mirbod

We present a numerical study of Rayleigh-B\'enard convection disturbed by a longitudinal wind. Our results show that under the action of the wind, the vertical heat flux through the cell initially decreases, due to the mechanism of…

Fluid Dynamics · Physics 2015-06-17 Andrea Scagliarini , Armann Gylfason , Federico Toschi

We investigate the influence of the thermal properties of the boundaries in turbulent Rayleigh-B\'enard convection on analytical upper bounds on convective heat transport. We model imperfectly conducting bounding plates in two ways: using…

Fluid Dynamics · Physics 2010-08-17 Ralf W. Wittenberg

The aspect ratio (\Gamma) dependence of the heat transfer (Nusselt number Nu in dimensionless form) in turbulent (two-dimensional) Rayleigh-B\'enard convection is numerically studied in the regime $0.4 \le \Gamma \le 1.25$ for Rayleigh…

Fluid Dynamics · Physics 2011-12-05 Erwin P. van der Poel , Richard J. A. M. Stevens , Detlef Lohse

We investigate the influence of the thermal properties of the boundaries in turbulent Rayleigh-Benard convection on analytical bounds on convective heat transport. Using the Doering-Constantin background flow method, we systematically…

Fluid Dynamics · Physics 2008-11-20 Ralf W. Wittenberg

To understand how internal flow structures manifest themselves in the global heat transfer, we study the correlation between different flow modes and the instantaneous Nusselt number ($Nu$) in a two-dimensional square Rayleigh-B\'enard…

Fluid Dynamics · Physics 2020-10-09 Ao Xu , Xin Chen , Feng Wang , Heng-Dong Xi
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