Variation of the Drag Coefficient with Wind and Wave State.
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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The dissipation method is used to obtain estimates for the friction velocity U sub , as well as values for the neutral drag coefficient, CDN, for data collected from a coastal tower off San Diego, California. C sub DN is found to be independent of the ten-meter height windspeed, U sub 10, for velocities between 4-9 msec. Its value is estimated to be 0.94 or - 0.41000 which compares well with values by Smith 1980 and Large and Pond 1981. Definite trends in C sub DN with fetch and sea state are also observed. Drag coefficient estimates are found to be higher for short fetch than for long fetch conditions. C sub DN is also seen to increase sharply just before frontal passages and during sea breeze conditions when the waves are actively growing. With the windspeed and wave field reaching equilibrium, C sub DN is found to decrease with time to a smaller and more constant value. Author
- Fluid Mechanics