Drag force and surface roughness measurements on freshwater biofouled surfaces

Abstract

The detrimental effect of biofilms on skin friction for near wall flows is well known. The diatom genera Gomphonema and Tabellaria dominated the biofilm mat in the freshwater open channels of the Tarraleah Hydropower Scheme in Tasmania, Australia. A multi-faceted approach was adopted to investigate the drag penalty for biofouled 1.0 m x 0.6 m test plates which incorporated species identification, drag measurement in a recirculating water tunnel and surface characterisation using close-range photogrammetry. Increases in total drag coefficient of up to 99% were measured over clean surface values for biofouled test plates incubated under flow conditions in a hydropower canal. The effective roughness of the biofouled surfaces was found to be larger than the physical roughness; the additional energy dissipation was caused in part by the vibration of the biofilms in three-dimensions under flow conditions. The data indicate that there was a roughly linear relationship between the maximum peak-to-valley height of a biofilm and the total drag coefficient.

Effect of barnacle fouling on ship resistance and powering

“…The plates were then towed down the tank using the types of coatings under static and dynamic conditions. Andrewartha et al (2010) measured an increase of 99% in the drag coefficients of test plates due to biofilms in a recirculating water tunnel. Monty et al (2016) carried out experimental and numerical studies and predicted a 34% increase in total resistance of a very large crude oil carrier due to light calcareous tubeworm fouling.…”

The CQ ratio of surface energy components influences adhesion and removal of fouling bacteria

“…Biofouling on the surfaces of heat exchangers, ships' hulls, pipelines, and other structures causes serious problems (Kerr et al 2003;Eguı´a et al 2008;Rao et al 2009;Andrewartha et al 2010). A thin layer of bacterial biofilm on the surfaces of heat exchangers significantly reduces heat transfer performance (Little and Lavoie 1979;Rao et al 2009).…”

Scanning Electron Microscopic Study of Slime Formations in a Water Injection Station of Oil India Limited in Assam, India

“…Gomphonema sp. have been reported from urban wetlands in India (Alakananda et al, 2013) and have been reported as the dominant biofouling diatom species on stainless steel surface biofilms after immersion in natural waters (Andrewartha et al, 2010). Recently, Yang et al (2015) while studying the seasonal variations in fouling diatom communities on the Yantai coast of China also reported Gomphonema sp.…”