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 static pressure within the tunnel is 51 mm of water below atmospheric. Assume that the air is incompressible and at 27oC, 101 kPa (abs). Calculate the air speed in the wind-tunnel test section. Assume that air obeys ideal gas equation.