Data description for: Wind tunnel data for knitted windbreak prototypes. 

Data File name: SharedDataWindtunnelTestsKnittedStructures_2022-11-07.xlsx

Data file description:
These data were collected for the study 
“Architectural knitted windbreaks for improved wind comfort in the city: A wind tunnel study of custom-designed porous textile screens”
The data includes measurements from wind tunnel tests during two occasions (2022-05-10 and 2022-07-14), for five knitted wind-break 
prototypes as well as two reference samples and a “zero-test”.

Principle investigator:
Erica Hörteborn, Department of Architecture and Civil Engineering, 
Division of Architectural Method and Theory, Chalmers University of Technology, Sweden.

Licensing:
Creative Commons Attribution 4.0 International (CC BY 4.0)

Methods:
The measurements were performed in a wind tunnel at Chalmers University of Technology. It is a closed-loop low-turbulence wind tunnel 
with a cross-sectional dimension of the test section of 1.8 m x 1.25 m. The wind tunnel has good flow uniformity (better than 1 %) 
and high flow stability. The incoming flow velocity was measured by a high-accuracy digital micromanometer with 0.5% accuracy. 
The micromanometer was connected to a Prandtl tube located in the wind tunnel inlet, approximately at a two-meter distance from the 
model. The air density was evaluated from the flow temperature and absolute pressure with 0.5% accuracy. The aerodynamic forces acting 
on the models were measured by a six-component balance with 1% accuracy. Only the drag force component was analysed in this study. The 
flow velocity behind the model was measured by a hot film anemometer from Dantec Dynamics with an accuracy of over 2 %. The anemometer 
was measuring the streamwise wind velocity without distinguishing the direction.
All the models were mounted on a steel frame, with all members having a circular cross-section of 10 mm. The frame was mounted on a 
six-component balance located under the floor outside the wind tunnel test section. The top and bottom of the textiles were held in 
place by a smaller steel rod (diameter: 3 mm and 2 mm). The total weight of the frame was 966 g.
The upstream velocities were approximately 3.5, 6, 8, 12.5 and 15 m/s (the slight variation between the test, was due to the blockage). 
These velocities correlate to the Beaufort scales of 3, 4, 5, 6 and 7, ranging from a gentle breeze to near gale [3]. These values were 
measured for each test, resulting in minor differences each time, as can be seen in the graphs in the result section. The models were 
tested at 4 different angles relative to the wind direction: 90°, 70°, 45°, and 20°. The wind speed downstream was measured with a 
hot-film anemometer at a position that would correlate to 5/8 H, where H is the height of the screen.

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Sheets and column headers:

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WindTunnelGathered (adjusted)
Collected data from measurements in windtunnel. No modifiactions has been made to the values, except that the Windspeed in (U) for 
sample 125 (acrylic, 90 deg, 10 m/s) is average value for 10m/s tests close in time, as the original data was lost. Hot film anemometer
output value is the measured value.

Units: 
windspeed: m/s , force (drag, “side-force”, lift): N, moments: Nm, temperature (T): deg. C, pressure: Pa, density: kg/(m^3), 
kinematic viscosity "nu": m^2/s

Column header: 
sample n. = sample number, correspond to the order in which the models were tested.
Sample	= The given name to sample, as described in the paper. 
Angle	= angle of the sample relative to the wind direction
Porosity = Calculated porosity of the sample (1 = non-porous, 0 = completely open)
Windspeed input = wind speed input for the wind tunnel
Date = date for the test, yyyymmdd	
time = time for test and film of test. (date and time can be used to find the film of the test. Note, however, that there is a slight discrepancy
between the given time and the clock on the GoPro)	
hot film anemometer output = measured wind speed behind the sample	
test name_reading = sample name in datafile from wind tunnel	
Windspeed in (U) = measured incoming wind speed	
drag = drag force acting on the sample (acting in the same direction as wind flow)	
"sideForce" = force sideways on the sample	
lift = upward force / lift force	
Moment L = moment around axis parallel to the wind	
moment M = moment around horizontal axis perpendicular to the wind	
Moment N = moment around vertical axis	
T = temperature
Pa = pressure 
rho = density of the air 
nu = kinematic viscosity

Note about measurements:
The six-component balance, measuring the aerodynamic forces acting on the models, were rotated between the days for the testing occations. Thus, 
for example the dragforce was measured as negative on 20220510 and possitive values on 20220714 (the rest of the forces should be adjusted accordingly). 
Therefore the coordinate system needs to be adjusted before testdata between the dates are compared.

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PorosityAndWeight
Porosity and weight values for the samples. Porosity is calculated through image analysis of a photo of the sample.

Units:
Weight g

Column header:
Sample	= The given name to sample, as described in the paper. 
weight = sample weight.
por. Processing = calculated porosity through script in Processing	
pattern percent = percentage of loose knit in pattern for sample or holes in case of the perforated sheet.

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Videofiles
List of associated videofiles of the tests.
Note that the times for "Date Modified" is not the exact same times as the times listed in the tab "WindTunnelGathered (adjusted)" as the clocks 
were not synced. The times vary with a maximum of 2 minuites (generally 1 min)

The video files are not contained in the dataset, but can be obtained on request from the principle investigator Erica Hörteborn.

Column header:
Name	
Size	
Date Modified


