The Experts below are selected from a list of 343119 Experts worldwide ranked by ideXlab platform

Jalel Azaiez - One of the best experts on this subject based on the ideXlab platform.

  • The impact of heterogeneous pin based micro-structures on Flow Dynamics and heat transfer in micro-scale heat exchangers
    Physics of Fluids, 2020
    Co-Authors: Mohammad Zargartalebi, Anne M. Benneker, Jalel Azaiez
    Abstract:

    Overheating is the most important limiting factor for efficient performance of miniature electronic devices. Porous microfluidic systems are recently introduced as a promising remedy to this problem. Increasing the heat removal using porous microfluidic systems comes at the cost of increased hydrodynamic friction in the device. In this study, we focus on the Flow Dynamics in microchannels with embedded heterogeneous porous structures to identify effective parameters to make porous patterns with less friction while maintaining a high heat transfer rate. The heterogeneous porous structures are defined using columns of pins with different pin sizes. We analyze the Flow Dynamics and heat transfer using quantitative and qualitative Flow patterns, energy distribution, and particle tracking analyses. We find that the structure of the porous medium plays an important role in the hydrodynamic Flow distribution and as a result on the overall heat transfer characteristics. While higher heat transfer rates in homogeneous porous media are proportional to higher friction, heterogeneous porous media revealed more complex Flow Dynamics. It was shown that an optimized distribution of the pins in the microchannel can lead to the systems where the heat transfer increases and, at the same time, the frictions decrease. We show that the columns at either end of the porous medium are the ones that affect Flow Dynamics and heat transfer the most.

  • Flow Dynamics and heat transfer in partially porous microchannel heat sinks
    Journal of Fluid Mechanics, 2019
    Co-Authors: Mohammad Zargartalebi, Jalel Azaiez
    Abstract:

    In this study, the Flow Dynamics and heat transfer in partially filled pin-based microchannel heat sinks (MCHS) are examined. The lattice Boltzmann method is used to analyse the physics of these systems and examine the effects of the Flow, pin configuration, size and porous medium height. The results of the study reveal that, unlike the fully filled pin-based MCHS, there is no unique behaviour for the pin configuration effects and the performance of partially filled pin-based MCHS depends on the porous medium size and structure as well as the inertial forces in the Flow. In particular, it is found that there are hydrodynamic and thermal-based critical porous medium heights at which the best performance in terms of heat removal switches from the inline to the staggered configuration. The dependence of these critical heights on the Reynolds number and the porous medium properties are analysed and the effects of the Flow Dynamics are further unravelled through a particle tracing technique. Furthermore, a simple Flow model is developed, and is shown to capture well the main trends obtained from the simulations and to bring to light more of the system physics that help explain the interplay between the different parameters.

J. Stuart Nelson - One of the best experts on this subject based on the ideXlab platform.

Mohammad Zargartalebi - One of the best experts on this subject based on the ideXlab platform.

  • The impact of heterogeneous pin based micro-structures on Flow Dynamics and heat transfer in micro-scale heat exchangers
    Physics of Fluids, 2020
    Co-Authors: Mohammad Zargartalebi, Anne M. Benneker, Jalel Azaiez
    Abstract:

    Overheating is the most important limiting factor for efficient performance of miniature electronic devices. Porous microfluidic systems are recently introduced as a promising remedy to this problem. Increasing the heat removal using porous microfluidic systems comes at the cost of increased hydrodynamic friction in the device. In this study, we focus on the Flow Dynamics in microchannels with embedded heterogeneous porous structures to identify effective parameters to make porous patterns with less friction while maintaining a high heat transfer rate. The heterogeneous porous structures are defined using columns of pins with different pin sizes. We analyze the Flow Dynamics and heat transfer using quantitative and qualitative Flow patterns, energy distribution, and particle tracking analyses. We find that the structure of the porous medium plays an important role in the hydrodynamic Flow distribution and as a result on the overall heat transfer characteristics. While higher heat transfer rates in homogeneous porous media are proportional to higher friction, heterogeneous porous media revealed more complex Flow Dynamics. It was shown that an optimized distribution of the pins in the microchannel can lead to the systems where the heat transfer increases and, at the same time, the frictions decrease. We show that the columns at either end of the porous medium are the ones that affect Flow Dynamics and heat transfer the most.

  • Flow Dynamics and heat transfer in partially porous microchannel heat sinks
    Journal of Fluid Mechanics, 2019
    Co-Authors: Mohammad Zargartalebi, Jalel Azaiez
    Abstract:

    In this study, the Flow Dynamics and heat transfer in partially filled pin-based microchannel heat sinks (MCHS) are examined. The lattice Boltzmann method is used to analyse the physics of these systems and examine the effects of the Flow, pin configuration, size and porous medium height. The results of the study reveal that, unlike the fully filled pin-based MCHS, there is no unique behaviour for the pin configuration effects and the performance of partially filled pin-based MCHS depends on the porous medium size and structure as well as the inertial forces in the Flow. In particular, it is found that there are hydrodynamic and thermal-based critical porous medium heights at which the best performance in terms of heat removal switches from the inline to the staggered configuration. The dependence of these critical heights on the Reynolds number and the porous medium properties are analysed and the effects of the Flow Dynamics are further unravelled through a particle tracing technique. Furthermore, a simple Flow model is developed, and is shown to capture well the main trends obtained from the simulations and to bring to light more of the system physics that help explain the interplay between the different parameters.

Vito Latora - One of the best experts on this subject based on the ideXlab platform.

  • Scaling and universality in river Flow Dynamics
    EPL (Europhysics Letters), 2011
    Co-Authors: M. De Domenico, Vito Latora
    Abstract:

    We investigate Flow Dynamics in rivers characterized by basin areas and daily mean discharge spanning different orders of magnitude. We show that the delayed increments evaluated at time scales ranging from days to months can be opportunely rescaled to the same non-Gaussian probability density function. Such a scaling breaks up above a certain critical horizon, where a behavior typical of thermodynamic systems at the critical point emerges. We finally show that both the scaling behavior and the break-up of the scaling are universal features of river Flow Dynamics. Copyright c EPLA, 2011

Arne Kesting - One of the best experts on this subject based on the ideXlab platform.

  • Traffic Flow Dynamics - Traffic Flow Dynamics
    2013
    Co-Authors: Martin Treiber, Arne Kesting
    Abstract:

    This textbook provides a comprehensive and instructive coverage of vehicular traffic Flow Dynamics and modeling. It makes this fascinating interdisciplinary topic, which to date was only documented in parts by specialized monographs, accessible to a broad readership. Numerous figures and problems with solutions help the reader to quickly understand and practice the presented concepts. This book is targeted at students of physics and traffic engineering and, more generally, also at students and professionals in computer science, mathematics, and interdisciplinary topics. It also offers material for project work in programming and simulation at college and university level. The main part, after presenting different categories of traffic data, is devoted to a mathematical description of the Dynamics of traffic Flow, covering macroscopic models which describe traffic in terms of density, as well as microscopic many-particle models in which each particle corresponds to a vehicle and its driver. Focus chapters on traffic instabilities and model calibration/validation present these topics in a novel and systematic way.  Finally, the theoretical framework is shown at work in selected applications such as traffic-state and travel-time estimation, intelligent transportation systems, traffic operations management, and a detailed physics-based model for fuel consumption and emissions

  • traffic Flow Dynamics data models and simulation
    2012
    Co-Authors: Martin Treiber, Arne Kesting
    Abstract:

    This instructional guide describes the use of simulation and mathematical models in determining traffic Flow Dynamics. Part 1 focuses on data collection with chapters on trajectory and floating-car data, cross-sectional data, and spatiotemporal reconstruction of the traffic state. Part 2 presents various mathematical models including: continuity equations, the Lighthill–Whitham–Richards Model, macroscopic models, car-following models, lane-changing models, stability analysis, and phase diagrams. Part 3 outlines traffic Flow theory applications. Chapters include: travel time estimation, fuel consumption and emissions, and optimization. This textbook includes problems and solutions and an accompanying website, www.traffic-Flow-Dynamics.org, provides some interactive content.