Does the barnacle settlement pattern affect ship resistance and powering?

Abstract

Predictions of increases in ship frictional resistance and powering were made for a range of barnacle fouling conditions. A series of towing tests were conducted using flat plates systematically covered with 3D printed barnacle tiles. The tests were set up to investigate the effect of barnacle settlement on the resistance and effective power of the ship. Therefore, a chaotic settlement which is called natural settlement, was designed to represent real barnacle settlement in nature. An extensive comparison was made between this natural settlement and the settlement that was designed in accordance with the standards. The drag coefficients and roughness functions values were determined and full-scale ship resistance and powering were estimated for six different ships at their cruise speed by using boundary layer similarity law. In addition, decreases in cruising speed due to barnacle fouling at fixed effective power were estimated as part of the case studies. The results indicate that settlement pattern caused up to ~10.5% difference in frictional resistance and ~6.7% difference in powering at cruise speeds whereas this settlement pattern caused up to ~20.5% speed reduction at fixed effective power.

Propeller Performance Penalty of Biofouling: Computational Fluid Dynamics Prediction

“…The adverse effects of biofouling on ship performance have been reported from the earliest times [1]. Accordingly, a large number of studies have been devoted to the roughness effect on ship resistance [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. According to the literature, the impact of calcareous (hard shell) fouling is particularly critical and highly dependent on the fouling type and coverage [2,3,9,10].…”

“…More recently, there have been studies utilising 3D printed artificial calcareous fouling models, e.g. barnacles, oysters or tubeworms [14,[17][18][19][20][21]. They observed significant increases in skin friction according to the sizes and coverage densities of the artificial fouling models.…”

Effect of biofouling roughness on a marine propeller's performance including cavitation and underwater radiated noise (URN)

“…This section provides a general literature review for the studies investigating the effects of biofouling on overall ship performance in the broad aspect, but with a keen interest in the propeller performance. There are many studies conducted in the literature focusing on the penalties caused by biofouling on ship hulls such as [1], [22], [23], [24], [25]. However, it is important to note that since it is a very distinctive subject, there are limited researches performed for investigating the effect of roughness on propeller performance, cavitation and noise.…”

“…It is important to note that roughness function vanishes for the smooth case (𝛥𝑈 + = 0), whereas it is determined experimentally for the rough cases. In this regard, Uzun et al [25] conducted an extensive series of towing tank tests of flat plates which are covered by 3D printed barnacle tiles in varying sizes, coverages and settlement patterns. Test configurations include three different barnacle sizes, percentages of coverage area ranging from 10% to 50% and two different settlement patterns.…”

“…First, ∆𝑈 + , and corresponding 𝑘 + values, provided in Uzun et al [25], were utilised in the wall function of the CFD software. After that, CFD simulations were performed based on the modified wall function of CFD model to predict the effect of roughness on the propeller blades.…”