On the definition of turbulent kinetic energy for flow in porous media

Pedras, Marcos H. J.; Lemos, Marcelo J. S. de

doi:10.1016/s0735-1933(00)00102-0

Cited by 118 publications

(65 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These models focused on the global flow characteristics in the REV and neglected detailed flow information. All the volume-averaging techniques on microscopic equations generate several additional terms to model the viscous and drag forces in porous media together providing closure problems for these additional terms (Antohe and Lage 1997;Nakayama and Kuwahara 1999;Getachew et al 2000;Pedras and de Lemos 2000;Chandesris et al 2006;Kuwahara et al 2006). Flow through a packed city can be assumed to be an incompressible turbulent flow in a rigid isotropic and fixed porous matrix with high Reynolds number.…”

Section: Introductionmentioning

confidence: 99%

Wind Conditions in Idealized Building Clusters: Macroscopic Simulations Using a Porous Turbulence Model

Hang

2010

Boundary-Layer Meteorol

View full text Add to dashboard Cite

Simulating turbulent flows in a city of many thousands of buildings using general high-resolution microscopic simulations requires a grid number that is beyond present computer resources. We thus regard a city as porous media and divide the whole hybrid domain into a porous city region and a clear fluid region, which are represented by a macroscopic k-ε model. Some microscopic information is neglected by the volume-averaging technique in the porous city to reduce the calculation load. A single domain approach is used to account for the interface conditions. We investigated the turbulent airflow through aligned cube arrays (with 7, 14 or 21 rows). The building height H, the street width W, and the building width B are the same (0.15 m), and the fraction of the volume occupied by fluid (i.e. the porosity) is 0.75; the approaching flow is parallel to the main streets. There are both microscopic and macroscopic simulations, with microscopic simulations being well validated by experimental data. We analysed microscopic wind conditions and the ventilation capacity in such cube arrays, and then calculated macroscopic time-averaged properties to provide a comparison for macroscopic simulations. We found that the macroscopic k-ε turbulence model predicted the macroscopic flow reduction through porous cube clusters relatively well, but under-predicted the macroscopic turbulent kinetic energy (TKE) near the windward edge of the porous region. For a sufficiently long porous cube array, macroscopic flow quantities maintain constant conditions in a fully developed region.

show abstract

Section: Introductionmentioning

confidence: 99%

Wind Conditions in Idealized Building Clusters: Macroscopic Simulations Using a Porous Turbulence Model

Hang

2010

Boundary-Layer Meteorol

View full text Add to dashboard Cite

show abstract

“…However, both sets of macroscopic mass transport equations are equivalent when examined under the recently established double decomposition concept [17][18][19][20][21][22]. As mentioned above, the double decomposition concept has been published in a number of widely available journal articles [17][18][19][20][21][22][23][24], book chapters [50][51][52][53] and a book [39]. For the sake of completeness, a brief overview is presented here and additional details can be found in the literature cited.…”

Section: Decomposition Of Flow Variables In Space and Timementioning

confidence: 99%

“…Also, the left superscript i represents spatial deviation. The double decomposition idea introduced and fully described elsewhere [17][18][19][20][21][22], combines Eqs. (1.15) and (1.16) and can be summarized as…”

Section: Decomposition Of Flow Variables In Space and Timementioning

confidence: 99%

“…When treating turbulent flow in porous media, however, difficulties arise due to the fact that the flow fluctuates with time and a volumetric average is applied [16]. For handling such situations, a new concept called double decomposition has been proposed for developing macroscopic models for turbulent transport in porous media [17][18][19][20][21][22]. This methodology has been extended to nonbuoyant heat transfer [23], buoyant flows [24][25][26][27][28][29][30], mass transfer [31] and double diffusion [32].…”

mentioning

confidence: 99%

“…In addition, a general classification of models has been published [33]. Further, the problem of treating interfaces between a porous medium and a clear region, considering a diffusion-jump condition for laminar [34] and turbulence fields [35][36][37], has also been investigated under the concept first proposed by several authors [17][18][19][20][21][22]. Furthermore, Saito and de Lemos (2006) [38] proposed a new correlation for obtaining the interfacial heat transfer coefficient for turbulent flow in a packed bed, which is modeled as an infinite staggered array of square rods.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Interfacial Heat Transport in Highly Permeable Media: A Finite Volume Approach

Lemos

Saito

2008

Cellular and Porous Materials

View full text Add to dashboard Cite

The transport of heat inside highly permeable media has attracted the attention of scientists and engineers due to its many engineering applications. Such applications can be found in solar energy receiver devices, heat exchangers, porous combustors, grain drying equipment, heat sink units, energy recovery systems, etc. In many of these modern engineering systems the use of cellular and metallic porous foams brings the advantages of having large specific heat transfer areas, or the interfacial transport area per unit volume is large when compared with other heat-capturing devices. More realistic modeling of transport processes in such media is then essential for the reliable design and analysis of high-efficiency engineering systems.Motivated by the wide spectrum of practical engineering applications, macroscopic transport modeling of incompressible flows in porous media has been developed over the last few decades, mostly based on the volume-average methodology for either heat [1] or mass transfer [2,3]. Classic books by Bear (1972) [4], Nield and Bejan (1992) [5] and Ingham and Pop (1998) [6], to mention a few, also document forced convection and related models for heat transport in porous media.From the point of view of energy transfer between phases, namely the cellular material phase and the working fluid, there are basically two different models commonly found in the literature: (a) a local thermal equilibrium model and (b) a two-energy equation or thermal nonequilibrium model. The first one assumes that the bulk solid temperature does not differ much from the average value of the fluid temperature; thus local thermal equilibrium between the fluid and the solid phase is assumed. This model greatly simplifies theoretical and numerical research but the assumption of local thermal equilibrium between the fluid and the solid is inadequate for a number of practical problems [7][8][9]. As a result, in recent years more attention has been paid to the local thermal nonequilibrium model, both theoretically and numerically [10,11].

show abstract

Heat‐Transfer Coefficient for Cellular Materials Modelled as an Array of Elliptic Rods

Lemos

Saito

2009

Adv Eng Mater

View full text Add to dashboard Cite

Convective heat‐transfer coefficients in foam‐like materials, modelled as an array of elliptic rods, are numerically determined. An incompressible fluid is considered, flowing through an infinite foam‐like material with an arbitrary solid temperature. A repetitive cell is identified and periodic boundary conditions are applied. Turbulence is handled with both low and high Reynolds number formulations. The interfacial heat‐transfer coefficient is obtained by volume integrating the distributed variables obtained within the cell. The results indicate that, for the same mass‐flow rate, materials formed by elliptic rods have a lower interfacial heat‐transfer coefficient compared to other media modelled as staggered arrays of square rods.

show abstract

On the definition of turbulent kinetic energy for flow in porous media

Cited by 118 publications

References 10 publications

Wind Conditions in Idealized Building Clusters: Macroscopic Simulations Using a Porous Turbulence Model

Wind Conditions in Idealized Building Clusters: Macroscopic Simulations Using a Porous Turbulence Model

Interfacial Heat Transport in Highly Permeable Media: A Finite Volume Approach

Heat‐Transfer Coefficient for Cellular Materials Modelled as an Array of Elliptic Rods

Contact Info

Product

Resources

About