Materials exposed in the marine environment, including those protected by antifouling paints, may rapidly become colonized by microfouling. This may affect frictional resistance and turbulent boundary layer structure. This study compares the mean and turbulent boundary layer velocity characteristics of surfaces covered with a marine bioflim with those of a smooth surface. Measurements were made in a nominally zero pressure gradient, boundary layer flow with a two-component laser Doppler velocimeter at momentum thickness Reynolds numbers of 5600 to 19,000 in a recirculating water tunnel. Profiles of the mean and turbulence velocity components, including the Reynolds shear stress, were measured. An average increase in the skin friction coefficient of 3 to 187 percent was measured on the fouled specimens. The skin friction coefficient was found to be dependent on both biofilm thickness and morphology. The biofilms tested showed varying effect on the Reynolds stresses when those quantities were nonnalized with the friction velocity.
The effect of biofilms on turbulent boundary layers
Wirkung von Biofilmen auf turbulente Grenzschichten
Transactions of the ASME, Series I. Journal of Fluids Engineering ; 121 , 1 ; 44-51
1999
8 Seiten, 9 Bilder, 5 Tabellen, 31 Quellen
Article (Journal)
English
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