Abstract
The three-dimensional flow field of a four-bladed propeller wake has been investigated by use of an anemometric hot film technique. The paper does not deal with the measuring procedure, which has been previously described by the authors, but describes the results obtained for the three-dimensional wake. To gain insight into the process by which local blade stalling influences the wake structure, four advance ratios (λ) have been investigated. The two lower values of λ correspond to a local blade stalling which first affects the blade tip and grows towards the hub with decreasing values of λ. The resultant velocity profiles of u, v, w in the azimuthal direction are investigated and compared at different advance ratios and at various radii. These experimental results reveal that a local flow separation has considerable influence on the three velocity components. It is concluded that for an advance ratio with rotor stalling, the flow separation increases the rotational wake speed effect generated by an increasing tangential component u. The radial flow diminishes as shown by the v velocity profiles. A sharp thickening of the blade wake is also observed from the axial component w.
