DAPPLE wind tunnel studies Hong Cheng Tom Lawton Paul Hayden Sandro Baldi Matteo Carpentieri Alan Robins

Presentation 30th November, 2004 Intersection studies - summary of work completed Flow visualisation Velocity field measurements sensitivity studies Dispersion measurements first tracer experiment sensitivity studies intersection

Sensitivity studies Dispersion: repeatability emission location and conditions model extent and detail reference speed and direction boundary layer conditions Flow: model extent and detail boundary layer conditions

Flow visualisation Smoke tracer with laser light sheet illumination recorded as stills and video: York Street sources horizontal and vertical light sheets Gloucester Place sources horizontal and vertical light sheets

Flow measurements LDA - U, V, W,,,,,, - spectra, correlations, pdfs Upstream boundary layer Roughness, canopy and outer layer Local flows - Gloucester Place, Marylebone Road intersection

Concentration measurements FFID - frequency response ~ 200 Hz: C,, pdf Steady emissions, various wind directions Short duration emissions (0.5 to 10s) - ensembles Sources at ground and roof level Ground level concentration distributions Cross-section profiles

Flow Visualisation

Flow visualisation - I

Flow visualisation - II Wind direction 51 degrees Marylebone Rd - Gloucester Pl. intersection Sources at Position X in York Street. Horizontal light sheet at height 20 mm.

Flow visualisation - III

Flow visualisation - IV

Flow visualisation - V

Velocity Field

Flow characteristics ? Marylebone Road East Gloucester Place North Strong 3 - dimensional flow Weak 3- dimensional flow

Mean velocity vectors - I Horizontal mean velocity vectors at heights of 5 and 20 m

Mean velocity vectors - II Mean velocity vectors at heights of 5 m

Mean velocity vectors - III Mean velocity vectors at heights of 5 m

Turbulence energy - I 1/2( + + )/U ref 2 at heights of 5 and 10 m

Turbulence energy - II 1/2( + + )/U ref 2 at heights of 15 and 20 m

Boundary layer measurements; (0, 0)

First Tracer Experiment

First tracer experiment

51˚ Sample point concentrations 44˚ 58˚ Simulation of 3 minute averages

Wind direction above WCC Profiles of mean wind direction above reference position on WCC for upper wind directions between 44 and 58 degrees. 44˚ 51˚ 58˚ 51˚ 17˚ North M. Rd

Concentration Measurement

Distributions at intersection Buildings 1-41 Buildings 1-37 Buildings 1-45 Intersection: -60 ≤ x ≤ 70 mm -130 ≤ y ≤ 90 mm Source at location X

Measurement locations York Street Crawford Street Gloucester Place Durweston St.

Canyon dimensions Crawford Street Durweston Street

Concentration contours along street centre-plane; H/W=3.7 Durweston Street roof level Above roof material from source region

Crawford Street; X=-320 mm Concentration contours in cross-section; H/W≈1.0 roof level

Crawford Street; X=-200 mm Concentration contours in cross-section; H/W≈1.0 roof level

Crawford Street; X=-100 mm Concentration contours in cross-section; H/W≈1.0 roof level

Crawford Street; Y=-1060 mm Concentration contours along street centre-plane; H/W≈1.0 roof levels

Future work  Completion of test case  Simulation of field tracer experiments  Mass balances - flux evaluations  Correlations and pdf analysis  Sensitivity to additional model detail - roofs - courtyards  Slightly stable and unstable flow conditions