Flow in Gillygate, York, UK, Street Canyon

The flow in the Gillygate Canyon, York, was modelled using the Smolarkiwicz Model ( Grabowski & Smolarkiewicz, 2002, MWR, 130, 939-56 and Prusa & Smolarkiewicz, 2003, JCP, 190, 601-622). Data for the set up can be found in Dixon et al, 2005, (submitted to Atmospheric Environment). In the current set up, three chemical tracers can be used. The model used is non-hydrostatic, anelastic, Eulerian with terrain following co-ordinates (Gall-Chen & Somerville, 1975). It has a periodic domain, defined by the dotted lines in the l.h. figure below with a uniform z0 of 0.1m, spatial resolution of 1m, and time step of 0.025s. Using neutral profile and an upstream initial wind velocity of u=5m/s from the right of the domain, the model is spun up for 30s. An inert tracer is inserted along the canyon, from the surface in a rectangle 50m long by 6m wide centred between the two lamp posts G3 and G4. The two movie loops below show 30s of simulation at 1s intervals, the centre pane shows the vertical velocity at 2m and the right hand pane, the concentration. (see poster ~ 2Mbytes ~ RCS, 2005, Faraday Poster ) The advantage of this approach is that a full meteorological equation set is used with dynamical and thermodynamical applicability. The street canyon can be nested within a larger scale meteorological domain, or used with a variable vertical and horizontal grid structure. The intention is to develop further applications.

  A map of Gillygate click on image for better resolution click on image for better resolution
Left panel ...: Map of Gillygate (model domain defined by dotted line). The two lamp posts, G3 and G4 are 12m apart.
Centre panel: 30*1s animation of w (+2m/s, red to -2m/s, blue). Sub-domain dx=50m , dy=55m, with the 2 lamposts marked
Right panel .: 30*1s animation of concentration. After a 30s spin up, the pollutant tracer is released after 1s. marked

Moto For further details email Sarah-Jane Lock or Alan Gadian

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20th April 2005