Academic Journal
Scalar fluxes from urban street canyons
| العنوان: | Scalar fluxes from urban street canyons |
|---|---|
| المؤلفون: | Janet F. Barlow, Ian N. Harman, Stephen E. Belcher |
| المساهمون: | The Pennsylvania State University CiteSeerX Archives |
| المصدر: | http://www.met.reading.ac.uk/~sws99jfb/publications/BHBpart1_final.pdf. |
| سنة النشر: | 2004 |
| المجموعة: | CiteSeerX |
| مصطلحات موضوعية: | turbulent flux, naphthalene sublimation, wind tunnel, street canyon |
| الوصف: | Flow over urban surfaces depends on surface morphology and interaction with the boundary layer above. However, the effect of the flow on scalar fluxes is hard to quantify. The naphthalene sublimation technique was used to quantify scalar fluxes out of a street canyon. For an array of eight canyons with aspect ratio H/W = 0.75, increased flux was observed in the first 2-3 canyons for moderate and low roughness upstream. This is consistent with predictions of the lengthscale for initial adjustment of flow to an urban canopy. The flux was constant after the initial adjustment region and thus dependent only on local geometry. For a street canyon in the “equilibrium” part of the array, each facet of the street canyon was coated with naphthalene to simulate scalar release from street, walls and roof, to evaluate the effect of street canyon geometry on fluxes for H/W = 0.25, 0.6, 1 and 2. Fluxes from the roof and downstream wall were considerably larger than fluxes from the street and up-stream wall and only the flux from the downstream wall exhibited a simple decrease with H/W. For each H/W there was a monotonic decrease between downstream wall, street and upstream wall transfer. This suggests that flow decelerates around the recirculation region in the lee of the upstream building, i.e. a recirculating jet rather than a symmetrical vortex. The addition of a second source within the street canyon resulted in reduced fluxes from each facet for H/W> 0.25 due to increased concentration of naphthalene in the canyon air. |
| نوع الوثيقة: | text |
| وصف الملف: | application/pdf |
| اللغة: | English |
| Relation: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.475.9825; http://www.met.reading.ac.uk/~sws99jfb/publications/BHBpart1_final.pdf |
| الاتاحة: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.475.9825 http://www.met.reading.ac.uk/~sws99jfb/publications/BHBpart1_final.pdf |
| Rights: | Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
| رقم الانضمام: | edsbas.8F23C11E |
| قاعدة البيانات: | BASE |
| الوصف غير متاح. |