Fluid Mechanics and Thermodynamics of Turbomachinery, 5e

196 Fluid Mechanics, Thermodynamics of Turbomachinery
FIG. 6.10. (a) Pressure variation in the neighbourhood of a rotating blade row.
(b) Axial velocity at the hub in the neighbourhood of a rotating blade row
(adapted from Hawthorne and Horlock 1962).
for a given incidence is, apart from Reynolds number and Mach number effects (cf.
Chapter 3 on cascades), fixed by the cascade geometry, a blade row of reduced width
may be considered to affect the flow in exactly the same way as the original row. In
the limit as the axial width vanishes, the blade row becomes, conceptually, a plane discontinuity
of tangential velocity—the actuator disc. Note that while the tangential