A SITE-BASED PRACTICAL IMPROVISATION FOR THE ANALYTICAL DETERMINATION OF ASPECT RATIO

Rajesh Gopinath, Deepak D.G

Abstract


'Aspect Ratio', a commonly used indicator to describe typical urban geometry is computed as the average ratio of the building heights ‘H’ to the canyon width 'W'. Its determination techniques in the present urbanization scenario is bound by certain assumptions which falter as most cities across globe does not project a well-planned street profile. An urban canyon factor is of most significance in climatic and air quality studies.
The study showcases how the standard assumptions cited in literatures for Urban Morphological Analysis cannot apply to most urban canyons in any townships that have evolved rampantly. The present research recommends a rationally feasible methodology of analytically ascertaining and representing Aspect Ratio for variant street canyons. The research objective envisaged selection of 3 random locations encompassing heterogeneous street canyon geometries. At each of these locations its land-use pattern and road network was mapped for a radius of 250m by supervised-classification to assist in extracting the canyon geometry features, namely building height and road width across all the streets.
The revised methodology judiciously delves upon when stations also have plots without pre-defined boundaries for creation of layouts. The logic encompasses complete dimensional analysis, and accounts for all four directions, the dynamic road width and building length measured along street about each focal point. The present research recommends this technique for a study of any magnitude; and encompassing just a street or even an entire city; as it’s practically applicable to any site condition and does away with errors due to the ‘idealistic’ assumptions.


Keywords


Aspect, canyon, dimensional, elevation, ratio, urban

Full Text:

PDF

References


Afiq, W.M.Y., Azwadi, C.S.N., Saqr, K.M. (2012). Effects of Buildings Aspect Ratio, Wind Speed and Wind Direction on Flow Structure and Pollutant Dispersion in Symmetric Street Canyons: A Review. International Journal of Mechanical and Materials Engineering, 7(2), pp. 158–165.

Ahmad, K., Khare, M., Chaudhry, K.K. (2005). Wind Tunnel Simulation Studies on Dispersion at Urban Street Canyons and Intersections-A Review. Journal of Wind Engineering and Industrial Aerodynamics, 93 (9), pp. 697–717. DOI: 10.1016/j.jweia.2005.04.002

Chan, A.T., Au, W.T.W., So, E.S.P. (2003). Strategic Guidelines for Street Canyon Geometry to Achieve Sustainable Street Air Quality-Part II: Multiple Canopies and Canyons. Atmospheric Environment, 37 (20), pp. 2761–2772. DOI: 10.1016/S1352-2310(03)00252-8

Chang, C.H., Meroney, R.N. (2003). Concentration and Flow Distributions in Urban Street Canyons: Wind Tunnel and Computational Data. Journal of Wind Engineering and Industrial Aerodynamics, 91(9), pp. 1141–1154. DOI: 10.1016/S0167-6105(03)00056-4

Chen-Yi Sun et.al. (2009). A Thermal Environment Investigation Of The Urban Street Canyon In A Hot And Humid City, Taichung City, Taiwan. In: Proceedings of The seventh International Conference on Urban Climate. Yokohama, Japan.

Eeftens, M. et.al. (2013). Quantifying urban street configuration for improvements in air pollution models. Atmospheric Environment, 72, pp. 1–9. DOI: 10.1016/j.atmosenv.2013.02.007

Gopinath, R. et al. (2014). An Analytical and Practically Feasible improvisation over representation of Sky-View-Factor. American International Journal of Research in Formal, Applied & Natural Sciences, 6(2), pp. 147–150.

Gopinath, R. et.al (2015). Change Recognition in Land-Cover Dynamics for Bengaluru (India) City due to Rampant Urbanization, using Quantum G.I.S. International Journal of Engineering, Business and Enterprise Applications, 13(1), pp. 34-36.

Gopinath, R., Akella, V., Bhanumurthy, P.R. (2014). Influence of Bengaluru (India)’s Canyon Geometry on the Intra-Urban Ambient Air Temperature. Scientific Herald of the Voronezh State University of Architecture and Civil Engineering, 23(3), pp. 40–50.

Marciotto, E., Oliveira, A.,Hanna, S. (2010). Modeling Study of the Aspect Ratio influence on Urban Canopy Energy Fluxes with a Modified Wall Canyon Energy Budget Scheme. Building and Environment, 45(11), pp. 2497–2505. DOI: 10.1016/j.buildenv.2010.05.012

Nicholson, S.E. (1967). A Pollution Model for Street-Level Air. Atmospheric Environment, 9, pp.19–31. DOI: 10.1016/0004-6981(75)90051-7

Oke, T.R. (1981). Canyon Geometry and the Nocturnal Urban Heat Island: Comparison of Scale Model and Field Observations, International journal of Climatology, 1 (3), pp. 237–254. DOI: 10.1002/joc.3370010304

Oke, T.R. (1988a). Street Design and Urban Canopy Layer Climate. Energy and Buildings, 11(1-3), pp. 103–113. DOI: 10.1016/0378-7788(88)90026-6

Oke, T.R. (1988b). The Urban Energy Balance. Progress in Physical Geography, 2(4), pp. 471–508. DOI: 10.1177/030913338801200401

Steyn, D.G. (1980). The Calculation of View Factors from Fish-Eye Lens Photographs. Atmosphere-Ocean, 18 (3), pp. 254–258. DOI: 10.1080/07055900.1980.9649091

Yamashita, S., Sekine, K., Shoda, M., Yamashita, K., Hara, Y. (1967). Studies on Relationships between Heat Island and Sky View Factor in the Cities of Tama River Basin, Japan. Atmospheric Environment, 20(4), pp. 681–686. DOI: 10.1016/0004-6981(86)90182-4




DOI: https://doi.org/10.23968/2500-0055-2017-2-3-11-20

Refbacks

  • There are currently no refbacks.




     
ISSN: 2500-0055