9. Physical Modeling
305
Air Hole
(b) Sectional view of OWC in
model
(a) Sectional view of OWC in
prototype
Hydrodynamic Parameters
Mass
Force
Pressure and stress
Energy and work
Power
Dimension
[M]
[MUT2]
[ML-1!-4]
[ML2!"2]
[ML2!-3]
Froude scale
a
Fig. 9.1 Géométrie, kinematic and dynamic similitude achieved by a model oscillating water column, OWC.
9.5 Scale Effects
Model scales are often derived from dimensional analysis or governing
équations. Complété similarity between model and prototype impossible
to achieve, since certain quantifies such as gravity, cannot be scaled down.
The parameters such as gravity, fluid viscosity and density are the same in
model as well as prototype. It is impossible to generate both gravity driven
and fluid viscous related phenomena concurrently. Waves and currents are
gravity-driven forces and in model studies it is preferred to simulate gravity
properly. This means that viscosity effects will not be properly reproduced.
The effects of such non-similarity are called scale effect.
9.6 Model Laws
The laws based on which the models are designed for dynamic similarity
are known as model laws or laws of similarity. The model laws are classified
based on their application as follows
• Reynold’s model law
• Froude’s model law