Wind Tunnel Tests of a Shrouded Aircraft Inlet

We describe tests of a shrouded aerosol inlet for a high-altitude jet aircraft. Both the lip of the inlet and the shroud are NACA (National Committee for Aeronautics, now known as NASA, or National Aeronautics and Space Administration) airfoils. Wind tunnel tests show a smooth growth of the boundary layer in the inlet, with an undisturbed core more than 1 m back from the entrance. The shroud makes the inlet performance insensitive to angle of attack. Aerosol transmission tests showed accurate sampling, although the Stokes numbers accessible in the wind tunnel were less than 0.2