Impact of diatomaceous biofilms on the frictional drag of fouling-release coatings.
Biofouling
; 31(9-10): 759-73, 2015.
Article
em En
| MEDLINE
| ID: mdl-26652667
ABSTRACT
Skin-friction results are presented for fouling-release (FR) hull coatings in the unexposed, clean condition and after dynamic exposure to diatomaceous biofilms for 3 and 6 months. The experiments were conducted in a fully developed turbulent channel flow facility spanning a wide Reynolds number range. The results show that the clean FR coatings tested were hydraulically smooth over much of the Reynolds number range. Biofilms, however, resulted in an increase in skin-friction of up to 70%. The roughness functions for the biofilm-covered surfaces did not display universal behavior, but instead varied with the percentage coverage by the biofilm. The effect of the biofilm was observed to scale with its mean thickness and the square root of the percentage coverage. A new effective roughness length scale (keff) for biofilms based on these parameters is proposed. Boundary layer similarity-law scaling is used to predict the impact of these biofilms on the required shaft power for a mid-sized naval surface combatant at cruising speed. The increase in power is estimated to be between 1.5% and 10.1% depending on the biofilm thickness and percentage coverage.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pintura
/
Navios
/
Fricção
/
Biofilmes
/
Incrustação Biológica
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Biofouling
Assunto da revista:
BIOLOGIA
Ano de publicação:
2015
Tipo de documento:
Article
País de afiliação:
Estados Unidos