Drag of Slimes on Rough and Smooth Surfaces as Measured by a Rotating Disk.

摘要

Attempts were made to grow microbial slime films of controlled roughness on circular disks in order to assess the effects of slime films on hydrodynamic drag. An attempt to grow bacterial and algae slimes in the laboratory did not yield a slime that was sufficiently rough to cause a significant effect on drag. Natural slime grown in bay salt water in the absence of an antifouling paint produced barnacles an/or vegetation growth which gave a drag increase. Two disks coated with antifouling paint, were set in bay water, resulting in a slime covering visually free of barnacles. A marked increase in drag was measured. However, the disks surface finish was sufficiently marred after the experimental evaluation, so that a definitive conclusion that slime by itself is a significant source of drag could not be reached. Further experiments are recommended to fully explore the effects of slimes on frictional drag. (Author)