Lifting Surface Hydrodynamics for Design of Rotating Blades

Analysis and numerical results are presented for the design of a system of wide-bladed thin lifting surfaces rotating at constant angular velocity in an axisymmetric onset flow field. Blade sections may be located arbitrarily in space. General chordwise and spanwise loading functions are available as well as a variety of thickness forms. In addition to the final meanline and pitch distribution determined from a chordwise·integration of an appropriate combination of geometric variables and induced velocities, additional information not available from other existing techniques includes pressure distributions and surface metrics for an orthogonal streamline coordinate system on the blade surface, as defined in the Appendix. The induced velocity field on the blades is derived from the principal value of a singular integral; the evaluation of this integral is discussed. The predictions are generally supported by experimental data. A new term in the analysis arises from a radial onset flow component and an example illustrates its importance in design. Sufficient information for manufacture is obtained for computer run times from 400 to 1200 seconds on the Burroughs 7700 high-speed computer.