An Investigation Into The Drag Increase on Roughen Surface due to Marine Fouling Growth (original) (raw)
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CFD Analysis into the Drag Estimation of Smooth and Roughened Surface Due to Marine Biofouling
IPTEK The Journal for Technology and Science, 2017
This study is to investigate drag on ship due to marine biofouling using CFD approach. A cargo ship with one year operation was used for the study and to examine the effect of biofouling between smooth and roughened hull by observing the result of CFD simulation. Simulation is done using CFD software based RANSE code together with SST based k-omega as turbulence setting and Grid Generator was used to build the hybrid grids. The result indicated that marine biofouling make significant increase for ship resistance up to 37 %. This fact is in good agreement with experimental test has been examined that fouling increases drag up to 80 % for two years. Keywords Hull Roughness, fouling, Fluid Dynamics, simulation, drag, power. AbstrakPenelitian ini untuk meneliti gaya hambat kapal yang diakibatkan oleh marine biofouling menggunakan pendekatan CFD. Kapal Cargo dengan satu tahun pelayaran digunakan untuk studi dan menguji efek biofouling antara lambung dengan permukaan halus dengan permukaan yang dikasarkan dengan mengamati hasil dari simulasi CFD. Simulasi dikerjakan dengan menggunakan software CFD berbasis RANSE dengan SST berbasis k-omega sebagai seting turbulen dan Grid Generator digunakan untuk membentuk hybrid grid. Hasil simulasi mengindikasikan bahwa marine biofouling meningkatkan gaya hambat yang bekerja pada kapal hingga 37 %. Fakta ini sesuai dengan pengujian eksperimen yang menyatakan bahwa fouling meningkatkan gaya hambat hingga 80 % dalam dua tahun.
IOP Conference Series: Earth and Environmental Science, 2019
This article will look into to the environmental and economic issues in the maritime sector that arise due to biofouling. For the shipping industry, biofouling is known to increase hull roughness that would lead to an increase in friction resistance and fuel consumption. Here we present a short review regarding ship-hull roughness due to biofouling and its associated increase in skin friction drag, and analysis of fuel consumption from an operating ship with two different anti-fouling coating. The data shows that a higher quality antifouling would result in a low biofouling attachment on the hull surface, resulting in a lower fuel consumption.
An investigation into the effect of biofouling on the ship hydrodynamic characteristics using CFD
Ocean Engineering
To reduce the fuel consumption and greenhouse gas emissions of ships, it is necessary to understand the ship resistance. In this context, understanding the effect of surface roughness on the frictional resistance is of particular importance since the skin friction, which often takes a large portion in ship drag, increases with surface roughness. Although a large number of studies have been carried out since the age of William Froude, understanding the roughness effect is yet challenging due to its unique feature in scaling. In this study, a Computational Fluid Dynamics (CFD) based unsteady Reynolds Averaged Navier-Stokes (RANS) resistance simulation model was developed to predict the effect of barnacle fouling mainly on the resistance and hull wake characteristics of the full-scale KRISO container ship (KCS) hull. Initially, a roughness function model was employed in the wallfunction of the CFD software to represent the surface conditions of barnacle fouling. A validation study was carried out involving the model-scale flat plate simulation, and then the same approach was applied in full-scale flat plate simulation and full-scale 3D KCS hull simulation for predicting the effect of barnacle fouling. The increase in frictional resistance due to the different fouling conditions were predicted and compared with the results obtained using the boundary layer similarity law analysis of Granville. Also, a further investigation of the roughness effect on the residuary resistance, viscous pressure resistance and wave making resistance was carried out. Finally, the roughness effect on the wave profile, pressure distribution along the hull, velocity distribution around the hull and wake flows were examined.
Jurnal Kelautan: Indonesian Journal of Marine Science and Technology
ABSTRACTThe presence of biofouling has an impact on the ship’s performance, which is reduced to require more fuel, in the end, it contributes significantly to cost increases. Biofilms provide a suitable substrate for the growth of microorganisms. Ship hull as a substrate for biofilms has many kinds of material. Steel, wood, laminated bamboo, and fiber are often used for ship hulls. Different material makes different characteristics of substrate for biofilms. The aim of this research is to determine the growth rate of biofouling in each shipbuilding material and to find out which vessel material is suitable for use in the Bali Strait. The experiment was located in Boom Marina, Banyuwangi. The materials used in this research are wood, laminated bamboo, and fiber. The daily growth rate (DGR) is calculated every week of observation. Wood had the most biofouling with a DGR of 2,646 g/day. Laminated bamboo had the least biofouling in this research after 2 months of immersion with a DGR of...
A Study on the Hydrodynamic Effect of Biofouling on Marine Propeller
Journal of the Korean Society of Marine Environment and Safety, 2016
The effect of propeller surface roughness condition on ship performance is very significant even the influence of fouling on propeller performance is not well established compared to biofouling on the hull surface. In present study, predictions of open water efficiency of propeller are made for three different fouling conditions, and its application is given for the 7m full-scale propeller of a medium-size tanker in open water condition. The numerical predictions of propeller efficiency loss due to fouling are based on the results from laboratory-scale drag measurements and boundary layer similarity law analysis presented in Schultz (2007) together with an in-house unsteady lifting surface code which is an appropriate tool to predict the effect of propeller surface roughness on propeller performance. The results of this study indicate that the subject propeller with the small calcareous fouling (ks=0.001) can lead to as high as 15 % loss at the propeller operating condition (J=0.5) and the loss of propeller efficiency due to fouling should be evaluated while the ship is operating.
A simplified approach for voyage analysis of fouled hull in a tropical marine environment
Ships and Offshore Structures, 2020
Tropical ocean environment teems with microorganisms, of which some adhere, either to the static ship hull or while en-route to the destination increasing roughness. A typical voyage analysis takes into account parameters like speed, power, propeller speed, displacement, fouling and weather conditions. Wind and wave data in the present study have been acquired from data buoys deployed along the voyage route from Chennai to Singapore. The differential equation of a ship undergoing acceleration is considered and solved to obtain voyage time and distance. Calculations to reach design speed were performed for various loading conditions. Limited experiments were performed in the towing tank using a ship model for various draft conditions. Granville's similarity law has been relied upon to arrive at the frictional resistance and is discussed in this paper. The loads due to wind and waves were specifically calculated for the ship with a fouled hull heading in its design speed.
Biofouling impacts on the environment and ship energy efficiency
2018
This dissertation is a study of the role of ship hull biological fouling in the transfer of invasive species. It has been shown on many reserahc that 70-80% of IAS (Invasive Aquatic Species) introductions occur through ship hull biofouling, and new areas are constantly being invaded. Data of case study ship are analyzed before and after maintenance operations of ship’s hull during dry dock. The results obtained have shown that the maintenance of the ship hull during dry-dock and the effectiveness of biofouling management system on board ships are significantly contributing to improve the ship’s speed and to reduce its fuel consumption, which reduces the GHG emission from ships. Furthermore, these methods limit the transfer of invasive species and their negative impacts. An overview of different stages of fouling formation on the ship’s hull and niche areas is given. The significant threat of aquatic invasive species transfer by ship hulls is assessed with a brief comparison of the c...
Fouling effect on the resistance of different ship types
Ocean Engineering, 2020
Considering that the ship hydrodynamic behaviours differ by the ship types and dimensions, the effect of biofouling on ship resistance can also vary with different ships. In this study, Unsteady Reynolds Averaged Navier-Stokes (URANS) based towed ship models were developed to simulate the roughness effect of biofouling on ship resistance. A container ship (KCS) and a tanker (KVLCC2), representing slender and a full hull forms, were modelled with various scale factors and speeds. The CFD simulations were conducted with several fouling conditions by embedding the roughness function of barnacles into the wall-function of the CFD model (i.e. modified wall-function approach). The fouling effects on the resistance components, form factors, wake fractions and the flow characteristics were investigated from the simulations. Significant differences were observed varying with the hull types, lengths (scales) and speeds of the ships and it was concluded that these differences are dominated by two parameters; relative roughness height and the roughness Reynolds number.
Gemi ve deniz teknolojisi, 2018
This paper reviews two decades of bridging the gap between laboratory measurements and predicting the performance of commercial maritime vessels and presents a rational approach, which is based on the combination of an experimental and a computational procedure, to predict the effects of modernday fouling control systems on "in-service" ship performance. Here the word "rational" reflects ship hull (and propeller) conditions as well as the approach to predicting the effect of the hull coating systems under such conditions. The proposed approach arguably provides a full solution to the complex ship performance problem. It is "rational" in terms of tackling the main features of modernday hull coating systems with the aid of bespoke experimental testing facilities and state-of-the-art computational methods. The proposed approach is generic and can be applied to any ship type and hull coating system in the presence of biofouling and it may even be combined with passive drag reduction systems. This approach involves both the combination of experimental data from flat test panels treated with representative surface finishes and extrapolation of this data to full-scale. However, for more accurate and direct estimation of performance prediction at full-scale, the extrapolation procedure needs to be replaced with Computational Fluid Dynamics (CFD) methods, especially for deteriorated hull surfaces due to fouling; at present, such experimental data are still required. The rational nature and hence strength of the proposed approach is to represent the effect of the actual hull surfaces "in-service" by using state-of-the art experimental methods and data. This provides the option of an extrapolation procedure for practical performance estimations and also enables the use of CFD methods by avoiding the most difficult barrier of describing the actual hull surface numerically in CFD. Validation of the proposed approach requires full-scale data to be collected using a bespoke ship performance monitoring and analysis system which is dedicated to assessing the effect of coating systems in the presence of fouling. Such a system is under development as detailed in an accompanying presentation.
Four KPIs for the assessment of biofouling effect on ship performance
Ocean Engineering, 2020
Biofouling accumulation on hull and propeller is one of the principal contributors to a ship's service performance losses. Ship Performance Monitoring Systems (SPMSs) are widely regarded as the primary means of monitoring the service performance decay of ships. The effect of fouling can be assessed by observing the change over time of parameters commonly termed Key Performance Indicators (KPI). Common KPIs are power increase and speed loss. These KPIs are, however, not enough to provide a clear perspective of the hydrodynamic vessel performance. This paper introduces three new KPIs in support of the common power increase KPI. These three KPIs need the propeller characteristics (e.g. open water curves) to be known, and one of them is based on the measurement of thrust. The method used to calculate them is described. The derivation of the reference performance baselines is demonstrated in applying this methodology to Newcastle University's Research Vessel "The Princess Royal". The concurrent analysis of all four KPIs is finally shown to provide more robust and detailed information regarding the source of the performance losses and their entity when compared to the real fouling state of this vessel.