WIND TUNNEL TEST ON CONVECTIVE MASS TRANSFER COEFFICIENT ON URBAN SURFACE : Study on convective heat transfer coefficient on outside building wall in an urban area Part 2

Narita, Kentaro; Nonomura, Yoshitami; Ogasa, Akira

doi:10.3130/aija.65.69_1

Cited by 6 publications

(27 citation statements)

References 1 publication

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“…Figure 5 shows the relationship between the normalised MTC of a 2-D canopy and H/W, the ratio of model height to street width. Narita et al (2000) confirmed that the relations between MTC and H/W have a similar tendency for wind speeds of 2, 4, and 6 m s )1 , and adopted their average. Barlow et al (2004) obtained the Stanton number from five cases with wind speeds ranging between 4 and 13 m s )1 .…”

Section: Effect Of Canopy Geometrysupporting

confidence: 73%

“…They clarified that the MTCs downstream of the second or third row were nearly equal regardless of variations of the vertical profile of the approaching flow. In spite of the differences of the measurement method, model size, and upstream condition, the results of Narita et al (2000) based on the evaporation method with filter paper show a similar tendency ( Figure 4). The MTCs decreases significantly from the first row to the third row.…”

Section: Scale-model Experimentssupporting

confidence: 61%

“…In addition, the normalised MTC of the vertical windward wall by Narita et al (2000) is close to 0.9 for the range of H/W=0.8-1.0. The relation between H/W and MTC of the windward wall of Narita et al, (2000) is similar to that of Barlow et al (2004). However, most MTC values of Barlow et al (2004) are larger than those of Narita et al (2000) under the same H/W.…”

Section: Effect Of Canopy Geometrymentioning

confidence: 86%

“…The MTCs are normalised by the results in each case for the roof with H/W=1. Barlow et al (2004) with the measured distribution by Narita et al (2000) in the next section.…”

Section: Effect Of Canopy Geometrymentioning

confidence: 96%

“…On the other hand, the MTCs of a street under conditions of skimming flow (H/W=1 and 2) are larger than those of the leeward wall. We will make another comparison of the MTC of a street by Narita et al (2000). (B) is the data of 8th row by Barlow et al (2004).…”

Section: Effect Of Canopy Geometrymentioning

confidence: 99%

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Intercomparisons of Experimental Convective Heat Transfer Coefficients and Mass Transfer Coefficients of Urban Surfaces

Hagishima

Tanimoto

Narita

2005

Boundary-Layer Meteorol

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The convective heat transfer coefficient (CHTC) of an urban canopy is a crucial parameter for estimating the turbulent heat flux in an urban area. We compared recent experimental research on the CHTC and the mass transfer coefficient (MTC) of urban surfaces in the field and in wind tunnels. Our findings are summarised as follows.(1) In full-scale measurements on horizontal building roofs, the CHTC is sensitive to the height of the reference wind speed for heights below 1. 5 m but is relatively independent of roof size.(2) In full-scale measurements of vertical building walls, the dependence of the CHTC on wind speed is significantly influenced by the choice of the measurement position and wall size. The CHTC of the edge of the building wall is much higher than that near the centre. (3) In spite of differences of the measurement methods, wind-tunnel experiments of the MTC give similar relations between the ratio of street width to canopy height in the urban canopy. Moreover, this relationship is consistent with known properties of the flow regime of an urban canopy. (4) Full-scale measurements on roofs result in a non-dimensional CHTC several tens of times greater than that in scale-model experiments with the same Reynolds number. Although there is some agreement in the measured values, our overall understanding of the CHTC remains too low for accurate modelling of urban climate.

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Section: Effect Of Canopy Geometrysupporting

confidence: 73%

Section: Scale-model Experimentssupporting

confidence: 61%

Section: Effect Of Canopy Geometrymentioning

confidence: 86%

“…The MTCs are normalised by the results in each case for the roof with H/W=1. Barlow et al (2004) with the measured distribution by Narita et al (2000) in the next section.…”

Section: Effect Of Canopy Geometrymentioning

confidence: 96%

Section: Effect Of Canopy Geometrymentioning

confidence: 99%

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