Wind Field and Aerodynamic Data for BARC in Downburst-like Flows (ERIES-TFCA - Volume 3)

Description

This research investigates fundamental flow around rectangular bluff bodies in atmospheric boundary layer (ABL), downburst (DB), and DB and ABL combined flows. The study focuses on three types of bluff bodies: a horizontally-extruded rectangular cylinder (like the internation benchmark model, BARC), a high-rise rectangular prism (like the CAARC standard tall building), and a Low-Rise Building (with similar cross-section dimensions to the CAARC standard). These body types can be regarded as fundamental models for studying structures such as long span bridges and buildings of varying heights. The project involves pressure measurements and Particle Image Velocimetry (PIV) of the flow around and in the near wake of these bluff bodies. The expected outcome is an improved capability in the prediction of the wind loads associated with downburst-like flows.

S1. Vertical Profile Rack

ABL, downburst-like, and the combination of downburst-like and ABL wind simulations were measured in a near-empty chamber. A rake of cobra probes. The height of the tallest model equals 90 cm. Thus, wind profiles will be measured using eight cobra probes mounted on a vertical stand at heights of 5 cm, 10cm, 15cm, 22.5cm, 30cm, 45cm, 70 cm, and 90 cm above the test chamber floor.

E1. Downburst-like Wind Profiling

Description:

An impinging-jet style downburst is generated at the WindEEE dome through the release of pressure from a plenum above the testing chamber. 3-D point measurements were taken to characterize the velocity profiles for downbursts. For the downburst simulations, two parameters were varied: the strength of the impinging jet flow and the position of the bell mouth (r_jet) in the WindEEE dome.

The vertical rack was positioned at a radial distance from the center of the turntable, r_jm = 320 cm, and with model angular position, φ = 180 degrees. The bell mouth position r_jet = -192, -128, -64, 0, and 64 cm from the centre of the turntable. These positions achieved r/D ratios of 1.6, 1.4, 1.2, 1, and 0.8. These measurements aim to provide detailed characteristics of the wind profile as it develops radially.

E2. Atmospheric Boundary Layer (ABL) Flow Profiling

Description:

The 60-fan wall located on one side of the hexagonal shaped WindEEE test chamber was used to generate the various ABL flows for this experiment. During the experiment, 3-D point measurements were taken to characterize the velocity profiles for numerous uniform smooth flow wind speeds.

The vertical rack was positioned at a radial distance from the center of the turntable, r_jm = 320 cm, and with model angular position, φ = 180 degrees.

E3. Combination Downburst-like and ABL Wind Profiling

Description:

In combination with the described downburst simulation in ‘S1. E2.’, these impinging-jets can be run simultaneously with the 60-fan wall (described in ‘S1. E1’) to achieve ABL and downburst-like flow combinations. During this experiment, 3-D point measurements were taken to characterize the velocity profile for a downburst with ABL wind.

The vertical rack was positioned at a radial distance from the center of the turntable (rm) at 320 cm and with φ=180. The bell mouth position r_jet = 0 cm from the centre of the turntable.

S2. BARC Pressure Model (M1)

A horizontally extruded rectangular cylinder of W x 5W x 20W, W = 300 mm, and equipped with endplates. 32 pressure taps are distributed along 9 pressure rings equally spaced along the horizontal direction. This body type can be regarded as a fundamental model for studying long span bridges.

E1. Downburst-like Wind

Description:

This experiment involves testing the static BARC pressure model under various simulated downburst flow profiles and strengths. The model was positioned 320 cm downwind from the center of the turntable facing the 60-fan wall (r_jm = 3.2 m, φ = 180°). In addition, the radial position of the impinging jet (r_jet) was varied relative to the model to achieve r/D = 0.8, 1.2, 1.4, and 1.6, only the downburst strength was varied for these positions, the angle of attack of the model stayed constant, a = 0°.  

E2. Atmospheric Boundary Layer (ABL) Flow

Description:

This test involved the BARC pressure model subjected to ABL flow at a wind speed of approximately 10 m/s. The model was positioned 320 cm downwind from the center of the turntable facing the 60-fan wall (r_jm = 3.2 m, φ = 180°). 

E3. Combination Downburst-like and ABL Wind

Description:

This test involved the BARC pressure model subjected to various downburst simulations involving combinations of impinging jet outflows and an ABL head wind of approximately 4-5m/s, generated from the 60-fan wall.  The model was positioned 320 cm (r_jm/D = 1.0) radially from the center of the turntable at angles of φ = 180°.

S7. PIV Profile Development

This specimen is supplementary to specimen 1. While specimen 1 captures point measurements in a vertical plane utilizing TFI cobra probes, this specimen captures flow field measurements utilizing the PIV system. A high-frequency laser was focused and split through a cylindrical lens into a thin laser sheet. Fog machines were used to seed the entire test chamber with long lasting fog fluid, and finally synchronized high-resolution cameras (flares) were used to capture laser light refraction. Flares send image data to the DVR Express Cores during test measurements.

E1. Downburst-like Wind

Description:

This experiment involves capturing various simulated downburst flow fields in a vertical plane. Depending on the instrumentation setup, the field coverage varies.

Instrumentation:

Four flares were each setup to cover an approximate total area of 30 cm by 225 cm, in height and length respectively. Three flares were set up with a 50mm lens to capture areas of approximately 30 cm by 80 cm, in height and length respectively. The overlap between these three flares was approximately 5cm. A single flare was set up with a 105 mm lens to capture an area of approximately 15 cm by 40 cm, in height and length respectively. Each flare uses automatic dual-exposure in high-resolution mode to capture data at a rate of 100Hz during a measurement. Dual exposure images are sequential from image 1-2, 3-4, 5-6, and so forth. The time delay between these exposures is 185 microseconds. Image data is identified by the following flare number schema K01, K02, K03, and K04.

An additional setup was also tested for this specimen. Four flares were each setup to cover an approximate total area of 30 cm by 150 cm, in height and length respectively. Two flares were set up with a 50mm lens to capture areas of approximately 30 cm by 80 cm, in height and length respectively. The overlap between these three flares was approximately 5cm. Two single flares were set up with a 105 mm lens to capture an area of approximately 15 cm by 40 cm, in height and length respectively. The larger area flares captured the broad picture of the flow, while the smaller area flares zoomed in on the flow around the specimen. Each flare uses automatic dual-exposure in high-resolution mode to capture data at a rate of 100Hz during a measurement. Dual exposure images are sequential from image 1-2, 3-4, 5-6, and so forth. The time delay between these exposures is 185 microseconds. Image data is identified by the following flare number schema K01, K02, K03, and K04.

E2. Atmospheric Boundary Layer (ABL) Flow

Description:

This experiment involves capturing a single simulated ABL flow field with an approximate wind speed of 10 m/s. Depending on the instrumentation setup, the field coverage varies.

Instrumentation:

Similar instrumentation was used as described in S8.E1.

E3. Combination Downburst-like and ABL Wind

Description:

This test involved capturing a vertical flow field for a single downburst simulation involving combinations of impinging jet outflows and an ABL head wind of approximately 4-5m/s, generated from the 60-fan wall.

S8. BARC PIV Model

This specimen is like specimen S2 but with black painted external surfaces and without pressure taps. PIV measurements were taken in a streamwise vertical plane at the model centre. A high-frequency laser was focused and split through a cylindrical lens into a thin laser sheet, fog machines were used to seed the entire test chamber with long lasting fog fluid, and finally synchronized high-resolution cameras (flares) were used to capture laser light refraction. Flares send image data to the DVR Express Cores during test measurements.

E1. Downburst-like Wind

Description:

This experiment involves testing the static BARC PIV model under a single simulated downburst flow profile. The model was positioned 320 cm (r_jm/D = 1.0) downwind from the center of the turntable facing the 60-fan wall (r_jm = 3.2 m, φ = 180°).

E2. Atmospheric Boundary Layer (ABL) Flow

Description:

This test involved the BARC PIV model subjected to ABL flow at a wind speed of approximately 10 m/s. The model was positioned 320 cm downwind from the center of the turntable facing the 60-fan wall (r_jm = 3.2 m, φ = 180°). 

E3. Combination Downburst-like and ABL Wind

Description:

This test involved the BARC PIV model subjected to a downburst simulation involving a combination of impinging jet outflow and an ABL head wind of approximately 4-5m/s, generated from the 60-fan wall.  The model was positioned 320 cm (r_jm/D = 1.0) radially from the center of the turntable at angles of φ = 180°. 

Series Information

This dataset is Volume 3 of 3, which together form the complete dataset for ERIES-TFCA.

Volume one includes datasets S0, S1, S3, and S5.

Volume two includes datasets S0, S4, S6, S7, S9, and S10.

Volume three includes datasets S0, S1, S2, S7, and S8.