The development of a laminar boundary layer on a twisted helical blade is described. An appropriate co-ordinate system is developed in which the boundary-layer equations have a relatively simple form. The choice of blade geometry and the free-stream conditions result in a constant-pressure flow. This permits the flow to be considered the analogue, in a rotating frame, of the zero-pressure-gradient flat-plate boundary layer in a stationary frame. The boundary-layer equations are solved using a double series expansion in powers of distance from the leading edge and the cosine of the blade twist angle. Chordwise and span wise velocity profiles are calculated. The variation in the skin friction coefficients is calculated as a function of position on the blade.
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering