Abstract
The results of the field measurements on the convection heat-transfer on the outside surface of two buildings in the built-up area are described in comparison with the case studied in the open field as in the preceding paper. The method and instrumentation of measurements are the same as used in the previous case; the relationships among the wind speed above the roof, air flow velocity near the surface and the convection heat-transfer coefficient turned out generally the same as obtained from the preceding experiments as shown in Fig. 4.3 through 4.12. It could be inferred that the air flow velocity near the surface beconsidered as the primary factor affecting the convection heat-transfer coefficient on the outside surface of the building. Some minor different characteristics were found with regard to the building shape, the degree of indention of building surfaces and the relative surface position in the entire wall. Being uncertain in this stage, however, these effects might be represented by the turbulence intensity of the air velocity near the surface as the secondary parameter, as the convection heat-transfer coefficient seems to decrease slightly with the increase of turbulence intensity as shown in Fig. 4.13. Fig. 5.3 shows that the relationship between the convection heat-transfer coefficient and the velocity of the air near the actual surface that behaves with irregular motion would be quite different with the one obtained from the conventional wind tunnel experiments where the air flow is parallel to the surface.
