This application example describes the measurement of the flow field in the cross section of an engine inlet duct within an 1:10 scale aircraft model. The model itself was mounted in the 3 × 3 m2 wind tunnel test section of DNW-NWB at DLR Braunschweig (Image of the model within the tunnel). The investigation was aimed at uncovering velocity inhomogeneities upstream of the engine as a function of the aircraft's angle of attack, yaw angle and air speed.
One of the reconstructed time-averaged flow fields obtained during the wind tunnel phase of the project is shown in the figure below. A strong vortical structure along with an unbalanced axial flow profile can be observed. Important design parameters can be derived from this type of data such as the total pressure loss and total pressure distortion.