The process of cavitation
in water has been involved in the damage of many types of man-made structures.
Flow speeds greater than 30 m/s appear necessary for cavitation damage.
Major damage can occur with flow depths of only a few meters but it
decreases with flow depth, channel roughness and air bubble content
of the water. A computer model predicting damage potential, calibrated
qualitatively with actual damages to dam spillways, is used to indicate
the locations and relative intensity of damage for several spillway
profiles. While damage is more likely associated with steeply sloping
channels, because of the high flow velocities achieved in them, damage
can occur in nearly horizontal surfaces if there is some other mechanism
for achieving the necessary flow speeds. In a hypothetical spillage
of water over the rim of the Grand Canyon, there are numerous locations
at which cavitation destruction of the rock would be as great or greater
than the worst damage ever seen in actual dam spillway. A flow of water
of only four meters (m) initial depth, approaching a rapid elevation
drop of less than 100 m at an initial speed of only 10 m/s can be expected
to produce major cavitation damage for a variety of natural land profiles.
The process of damage by cavitation appears to be a likely mechanism
for rapid removal of rock in channels experiencing catastrophic flows
of high speed shallow water with little air bubble content.
CONSTANTS AND THE COSMOS
Four different theories
of variable fundamental physical constants are reviewed and compared.
Special emphasis is placed on problems of interest to the creationist.
The number of explanations for difficult and diverse diluvial problems
available from these types of theories, as well as their application
to the problems of light from distant galaxies and radioactivity, makes
this field a most interesting one from the creationist perspective.
ON THE VIABILITY
OF VARIABLE CONSTANTS
The feasibility and implications
of variations in the fundamental constants are examined. Although such
proposed changes appear at present to be strongly ad hoc, it is argued
that this is not a fatal deficiency. The apolgetic function of theorizing
is briefly discussed. The distinction between operation and origin science
is emphasized. It is suggested that more emphasis should be placed on
the underlying philosophical issues.
VARIABLES MODEL FOR THE SPEED OF LIGHT
The speed of light is thought
to be a fundamental constant of physics. This paper proposes a model
for allowing the speed of light, c, to be changing with time. It is
shown that a decaying exponential with the appropriate boundary conditions
would accommodate the apparently constant value for c that modern measurements
have provided, even if the value of c is changing.