A baseline study of the effect of freshwater biofilms in an hydraulic conduit

A program is underway at the University of Tasmania investigating ways to control biological growths in hydraulic conduits. The broad aim of this research is to minimise the effects of biological growths to optimize conduit performance and maintenance procedures, and increase the economic return from existing hydraulic infrastructure. This paper presents results from experiments carried out on a newly constructed re-circulating water tunnel purpose built to investigate the effect of freshwater biofilms in hydraulic conduits. A baseline study of boundary layer velocity profiles and total drag measurements of a specially prepared rough test plate has been conducted to determine the plate's roughness characteristics. Experimental measurements from the water tunnel are complemented with three-dimensional physical roughness data obtained from innovative photogrammetric methods. The roughness data from the water tunnel and photogrammetry are compared and are shown to agree by within 20%.