TABLE OF CONTENTS Engineering analyses generally begin with an observation of the principles of physics that govern a physical phenomena. After these principles of physics have been carefally identified, a mathematical model may be developed that approximates these principles of physics. The careful selection of a mathematical model is always done after the physics have been carefully evaluated. It is crucial that a coastal or ocean engineer never juxtapose the sequence of these two elements in the engineering design and analysis.
In this spirit, an observer standing on the boat landing near one of the corner jacket legs of a pile-founded steel jacket structure would observe visually that this leg has no sensible effect on the incident wave field. Under careful observation, especially in the case of long-crested waves, the observer could see or not see the following two major physical phenomena:
| Seen: | The observer would see flow separation around the slender jacket leg that results in vortex shedding and wake turbulence on the down-wave side of the jacket leg. In addition, some slight decrease in the water surface elevation may be seen in this down-wave, turbulent-wake zone. |
| Not Seen: | The observer would not see the incident wave modified significantly by the slender jacket leg. Additionally, if this platform were free to respond with dynamic motions such as in a small, semi-submersible buoy, no radiated waves would be observed radiating away from the slender member or buoy. |
In contrast to what is seen or not seen in the case of a...
