EXP 1-2 Description: Difference between revisions
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= | =Pollutant transport between a street canyon and a 3D urban array as a function of wind direction and roof height non-uniformity= | ||
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= Description of Study Test Case = | = Description of Study Test Case = | ||
The following figures show schematically the general set-up of the wind tunnel experiment and the cases investigated. In general, the urban model (either with even height, marked A1, or with uneven height, marked A2) was positioned in the middle of the wind tunnel test section (Fig. 1a). To simulate the oblique wind direction, the model was rotated 45 degrees in its centre (corresponding to the centre of the coordinates <math>x,z,y</math>). The studied street canyons were positioned in the middle of the urban model (green rectangles in Fig. 2a and b), as well as the line source near the ground (the red line in Fig. 2a and b). For model A1, only the right street canyon (designated A1-R, viewed from downstream) was investigated due to symmetry, while the right (A2-R) and left (A2-L) street canyons were investigated in model A2 due to the uneven roof height. Upstream of the model, a neutrally stratified atmospheric boundary layer was simulated using roughness elements and Irwin spires in the development section of the wind tunnel. Based on the mean height of the building (<math>H</math>) and the free flow velocity <math>U_{ref} = 6.2</math> <math>ms^{-1}</math> (which was used as the reference velocity), the flow was completely independent of the Reynolds number (i.e. <math>Re_{B} = HU_{ref}/\nu = 24400</math>, where <math>\nu</math> is the kinematic viscosity of the air). | The following figures show schematically the general set-up of the wind tunnel experiment and the cases investigated. In general, the urban model (either with even height, marked A1, or with uneven height, marked A2) was positioned in the middle of the wind tunnel test section (Fig. 1a). To simulate the oblique wind direction, the model was rotated 45 degrees in its centre (corresponding to the centre of the coordinates <math>x,z,y</math>). The studied street canyons were positioned in the middle of the urban model (green rectangles in Fig. 2a and b), as well as the line source near the ground (the red line in Fig. 2a and b). For model A1, only the right street canyon (designated A1-R, viewed from downstream) was investigated due to symmetry, while the right (A2-R) and left (A2-L) street canyons were investigated in model A2 due to the uneven roof height. Upstream of the model, a neutrally stratified atmospheric boundary layer was simulated using roughness elements and Irwin spires in the development section of the wind tunnel. Based on the mean height of the building (<math>H</math>) and the free flow velocity <math>U_{ref} = 6.2</math> <math>ms^{-1}</math> (which was used as the reference velocity), the flow was completely independent of the Reynolds number (i.e. <math>Re_{B} = HU_{ref}/\nu = 24400</math>, where <math>\nu</math> is the kinematic viscosity of the air). | ||
Revision as of 12:05, 9 May 2023
Pollutant transport between a street canyon and a 3D urban array as a function of wind direction and roof height non-uniformity
Description of Study Test Case
The following figures show schematically the general set-up of the wind tunnel experiment and the cases investigated. In general, the urban model (either with even height, marked A1, or with uneven height, marked A2) was positioned in the middle of the wind tunnel test section (Fig. 1a). To simulate the oblique wind direction, the model was rotated 45 degrees in its centre (corresponding to the centre of the coordinates ). The studied street canyons were positioned in the middle of the urban model (green rectangles in Fig. 2a and b), as well as the line source near the ground (the red line in Fig. 2a and b). For model A1, only the right street canyon (designated A1-R, viewed from downstream) was investigated due to symmetry, while the right (A2-R) and left (A2-L) street canyons were investigated in model A2 due to the uneven roof height. Upstream of the model, a neutrally stratified atmospheric boundary layer was simulated using roughness elements and Irwin spires in the development section of the wind tunnel. Based on the mean height of the building () and the free flow velocity (which was used as the reference velocity), the flow was completely independent of the Reynolds number (i.e. , where is the kinematic viscosity of the air).
Contributed by: Štěpán Nosek — Institute of Thermomechanics of the CAS, v. v. i.
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