Abstract:
This thesis presents the results of an experimental investi
gation concerning the mechanism of resistance to flow over
two-dimensional sharp-edged roughness elements of negligible
thickness. The studios viere carried out in a tilting flume
with water and also in two wind tunnels, one of them being an
open r"'rcult tunnel & other of the closed-circuit type. Experi
ments were carried out to cover the following aspects of the
problem :-
a) Effect of contraction of the stream on the drag
coefficient o^ sharp-edged plates.
b) Effect of submergence of a normal plate in a
turbulent boundary on the drag coefficient of "^he
plate.
c) Porm resistance of an element kept in series on a
plane boundary and the total resistance of the plane
boundary.
d) Effect of introduction of a small roughness element
in the wake of a large oni_ on the resistance
characteristics of both the elements.
In addition to the aspects mentioned above, information has
also been obtained on the nature of velocity distribution in
the flow over artificial roughness elements and on the location
of datum as related to the relative spacing of the roughness
elements . Also the applicability of the method suggested
by Morris to the type of roughness elements used in this
study has been examined.
The conclusions derived on the basis of the
analysis of. data concerning the various aspects mentioned
above afford a better insight into the problem of resistance
of artificial roughness elements.
