The Prediction of Boundary-Layer Behaviour and Profile Drag for Infinite Yawed Wings: Part I A Method of Calculation
نویسندگان
چکیده
SUMMARY Cumpsty and Head's entrainment method for turbulent boundary layers is extended to compressible flow using Green's compressibility assumptions. The laminar layer is predicted using Thwaites' method in the chordwise plane and the Nath method spanwise. The Rott compressibility transformation is used. The transition and wake assumptions are consistent with the two-dimensional profile drag method of Nash. The complete method, suitable for use in making routine design calculations, is described briefly. The relationships between calculation time, step length and accuracy are considered for a practical infinite wing at transonic cruise conditions. The global iteration technique adopted earlier by Cumpsty and Head is shown to fail in regions of favourable pressure gradient, just downstream of the leading edge, as 'correction' terms involving derivatives of integral cross-flow thicknesses are no longer small. A much faster step-by-step numerical method has been adopted to solve the differential equations of the integral turbulent boundary-layer method without convergence problems.
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