Abstract:
A
unifying principle was discovered to treat square-wave,
steady state, circumferential temperature distortions at arbitrary
levels of distorted stagnation pressure, applicable to the low
speed range., ' '
A
velocity transformation was found to relate the physical 4
properties of a two-dimensional, non-viscous flow field collectively,
to the\introduced modified velocity. Furthermore, the flow in the
modified plane retains the characteristics of classical incompressible
flow
and, in general, is rotational.
The flow was divided into regions of either constant or linearly â
º
varying modified velocities. Each two regions were separated by a
free streamline initíally of unknown position. A non-linear,large
disturbance,mathematical model was set-up to find out the correct
free streamlines location in the
presence of a single aerofoil.
Considering first order derivatives of the induced modified velocities
of the flow modified vortices and the aerofoil,.when applying a
modified continuity equation,_the model converges rapidly.
-
.Results showed the aerofoil lift coefficient to fluctuate above
and below its undistorted
value, near the regions of shear flow,~º -
depending on the relative directions of the flow modified vortices,
and the circulation around the aerofoil - « .
.
Experimental investigations included tests on«a single blade'
'mounted near the intake of an axial
compressor of constant annulus -
height. Results showed that at this level of temperature distortions _
the stagnation pressure of the distorted flow had a dominant effect on the
behaviour of the lift coefficient.
