ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
CONVEX CURVATURE EFFECTS ON THE HEATED TURBULENT BOUNDARY LAYER
Abstrakt
Wall heat transfer rates and profiles of mean
velocity and temperature were measured for a turbulent
boundary layer flow on a heated, isothermal,
convexly curved wall of 45 cm radius of curvature.
For the base case the ratio of boundary layer
thickness to radius of curvature, δ(99)/R, was
0.10. Some data was also presented for a comparison
case of δ(99)/R = 0.05. Curvature effects were
significant. In the curved region, the Stanton
numbers and skin friction coefficients were reduced
by 35-40 percent below flat plate values for
the same momentum or enthalpy thickness Reynolds
numbers, and recovered slowly on a flat wall downstream
of the curved wall. After 60 cm, Stanton
numbers and skin friction coefficients were still
15-25 percent below flat-wall values. Profiles
of mean velocity and temperature show a more rapid
growth of the wake regions and a shortening of the
log-linear region as a result of curvature. Recovery
of the profiles is slow and by propagation outward
from the wall. Turbulent Prandtl numbers, deduced
from the mean temperature profiles assuming a
thermal law of the wall, were increased 40-50 percent
by this strong convex curvature.