Sixth Symposium on the Urban Environment


The momentum and turbulent kinetic energy budgets within the Oklahoma City Park Avenue street canyon

Matthew A. Nelson, LANL, Los Alamos, NM; and M. J. Brown and E. Pardyjak

Sonic anemometer data were taken in, around and above the Oklahoma City, Oklahoma Park Avenue street canyon during the Joint Urban 2003 field campaign. The anemometers were deployed on multiple towers at the base of the canyon and on the roofs of the buildings bounding the canyon. These data are used to explore the momentum and turbulent kinetic energy (TKE) budgets within a real-world urban core in an area devoid of major topographical features. The storage, advection, viscous, and turbulent flux terms of the mean momentum budget will be presented. The storage, advection, buoyancy, mechanical shear production, and turbulent flux terms of the TKE budget will be presented. A region of flow at the base of the urban canopy sublayer (UCSL) has been observed where the turbulence tends to be highly disorganized. This so-called “disorganized sublayer” (DSL) is characterized by the Reynolds shear stresses being small relative to the normal stresses. The nature of the flow within the UCSL and DSL makes it difficult to simplify the momentum and TKE budgets since very few terms can be neglected a priori. The characteristic small Reynolds shear stresses within the DSL are likely to have a greater effect in the TKE budget than the momentum budget. This is due to the fact that the turbulent flux terms in the momentum budget involve the gradients of the Reynolds stresses rather than their magnitudes, whereas the mechanical shear production term of the TKE budget involves the actual Reynolds stresses. The momentum and TKE budgets will provide further insight into the physical processes dominating the highly complicated mean and turbulent flow characteristics within a street canyon.

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Session 4, Urban Boundary-Layer Structure and Development (Cosponsored by BL&T committee)
Tuesday, 31 January 2006, 1:45 PM-5:45 PM, A315

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