Variation of the Drag Coefficient with Wind and Wave State

Download or read book Variation of the Drag Coefficient with Wind and Wave State written by Beverly J. Byars and published by . This book was released on 1985 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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 m/sec. Its value is estimated to be (0.94 + or - 0.4)1000 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).