18 in. Open Circuit Vertical Wind Tunnel

The vertical wind tunnel has a 45 cm x 45 cm x 60 cm (18 in. x 18 in. x 24 in.) test section and is capable of airflow velocities from 1 to 12 m/s. The contraction has a 6.25:1 area ratio, with a symmetric cross section and analytically developed contours. The primary diffuser section expands with a total included angle of 6 degrees. The inlet section includes an aluminum honeycomb section and graduated mesh, high porosity screens providing a velocity variation in the test section of less than 1% variation from the mean, free stream velocity. Airflow velocity is controlled by a transistor invertor type variable frequency controller and velocity measurements are made using a hot wire and/or vane anemometer. Thermocouple temperature readings and resistive heater power levels are measured, recorded and controlled using a Keithley data logger connected to an IBM PC compatible computer.