Introduction:

A large-scale direct-flow suction-type low-speed boundary layer wind tunnel is a specialized experimental facility designed to study the airflow characteristics within the atmospheric boundary layer. It is primarily used to simulate low-speed airflow conditions in natural environments, making it particularly suitable for aerodynamic research in fields such as urban planning, architectural design, environmental engineering, and aerospace.

Structural Features

1. Direct-Flow Suction Design:

? Unlike traditional closed-circuit wind tunnels, the direct-flow suction-type wind tunnel uses a powerful exhaust fan system at the outlet to draw air in from the entrance and discharge it into the external environment, creating a unidirectional airflow.

? This design helps reduce the effects of backflow and turbulence, providing a more stable and smooth airflow field.

2. Contraction and Diffusion Sections:

? Contraction Section: Located at the front of the wind tunnel, its function is to gradually narrow the channel cross-section to accelerate the airflow speed before it enters the test section, while improving the uniformity and stability of the airflow.

? Diffusion Section: Located at the rear of the wind tunnel, it is responsible for decelerating the airflow and discharging it smoothly to prevent excessive energy loss.

3. Test Section:

? As the core area, the test section typically has large dimensions (e.g., width up to several meters) to accommodate large-scale models or full-scale architectural models for testing.

? The test section is equipped with high-precision measurement devices, such as pressure sensors and hot-wire anemometers, for accurately measuring airflow parameters.

4. Flow Straightening Device:

? A honeycomb or grid-type flow straightener is installed at the entrance to eliminate the influence of external disturbances on the airflow, ensuring that the airflow entering the test section is as uniform as possible.

5. Boundary Layer Generation Device:

? Specially designed rough surfaces or obstacles can be used to simulate terrain variations in nature, thereby generating atmospheric boundary layer characteristics that conform to real-world conditions.

Parameters:

1. Direct-Flow Suction-Type Low-Speed Boundary Layer Wind Tunnel:

2. Specifications: Length × Width × Height = 50.3m × 3m × 2.5m, test section length 28m, wind speed range 0.2～30m/s. Laboratory floor area approximately 3730m2.

3. Currently equipped main testing devices include: 2 wind-finding theodolites, 2 QDF-3 hot-bulb anemometers, 1 hot-wire anemometer produced by DISA (Denmark), and 2 computers.