Example 65. An open circuit wind tunnel draws in air from the atmosphere through a well-contoured nozzle. In the test section, where the flow is straight and nearly uniform, a static pressure tap is drilled into the tunnel wall. A manometer connected to the tap shows that the static pressure within the tunnel is 45 mm of water below atmosphere. Assume that air is incompressible and the test section pressure is 100 kPa (absolute). Calculate the velocity in the wind tunnel section (Refer to Fig: 6.6). Density of water is 999 kg/m³ and the characteristic gas constant for air is 0.287 kJ/(kg·K).