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1.
This paper proposes a Computational Fluid Dynamics (CFD) based unsteady RANS model which enables the prediction of the effect of marine coatings and biofouling on ship resistance and presents CFD simulations of the roughness effects on the resistance and effective power of the full-scale 3D KRISO Container Ship (KCS) hull.Initially, a roughness function model representing a typical coating and different fouling conditions was developed by using the roughness functions given in the literature. This model then was employed in the wall-function of the CFD software and the effects of a typical as applied coating and different fouling conditions on the frictional resistance of flat plates representing the KCS were predicted for a design speed of 24 knots and a slow steaming speed of 19 knots using the proposed CFD model. The roughness effects of such conditions on the resistance components and effective power of the full-scale 3D KCS model were then predicted at the same speeds. The resulting frictional resistance values of the present study were then compared with each other and with results obtained using the similarity law analysis. The increase in the effective power of the full-scale KCS hull was predicted to be 18.1% for a deteriorated coating or light slime whereas that due to heavy slime was predicted to be 38% at a ship speed of 24 knots. In addition, it was observed that the wave resistance and wave systems are significantly affected by the hull roughness and hence viscosity. 相似文献
2.
珠江口东南近海海区污损生物研究 总被引：4，自引：2，他引：4
为研究珠江口东南近海海区污损生物状况,于1986年5月至1987年6月,在香港东南约114和160km,水深为95和113m处布设了两个生物浮标站,并对距香港约172km,水深为115m处的Marex水文气象浮标上的污损生物群落进行调查.此次调查共采集和鉴定出污损生物78种,其中在浸海只有3个月的试板上,主要有柄蔓足类、水螅和藻类,优势种是细板条茗荷、茗荷和直杯螅.至于浸海时间达6～12个月的浮标(包括沉标)及锚链系统,其上还有相当数量的多种双壳类软体动物、无柄蔓足类和苔藓动物等硬性污损生物附着.在种类垂直分布方面,污损生物群落组成随深度发生明显变化. 相似文献
3.
Richardson BJ Lam PK Zheng GJ McClellan KE De Luca-Abbott SB 《Marine pollution bulletin》2002,44(12):1372-1379
The outer layers of layflat, low density polyethylene plastic tubing (the principal component of semi-permeable membrane devices, SPMDs) were biofouled at a clean site in Hong Kong coastal waters for periods of 1–4 weeks. Following pre-fouling, triolein was added to the SPMDs and, along with control (unfouled) devices, they were exposed to a range of organochlorine pesticides (-HCH, aldrin, p,p′-DDT) and PAHs (anthracene, fluoranthene and benzo(a)pyrene) under laboratory conditions. Results showed that the uptake of contaminants by SPMDs was severely reduced by as much as 50% under fouling conditions in comparison to unfouled controls. The ultimate utility of SPMDs as passive monitors is thus reduced, although alternative measures, such as the use of permeability reference compounds may compensate, and allow for realistic evaluations of dissolved environmental concentrations in aquatic environments. However, due to the complexities involved in such procedures––especially as they need to be conducted on a case-by-case basis––the utility of SPMDs appears to be limited for estimates of bioavailability unless necessary calibrations are undertaken within each environment that the sampler is used. 相似文献
4.
Irgarol 1051 (2-methythiol-4-tert-butylamino-6-cyclopropylamino-s-triazine) is an algaecide commonly used in antifouling paints. It undergoes photodegradation which yields M1 (2-methylthio-4-tert-butylamino-6-amino-s-triazine) as its major and most stable degradant. Elevated levels of both Irgarol and M1 have been detected in coastal waters worldwide; however, ecotoxicity effects of M1 to various marine autotrophs such as cyanobacteria are still largely unknown. This study firstly examined and compared the 96 h toxicities of Irgarol and M1 to the cyanobacterium Chroococcus minor and two marine diatom species, Skeletonema costatum and Thalassiosira pseudonana. Our results suggested that Irgarol was consistently more toxic to all of the three species than M1 (96 h EC50 values: C. minor, 7.71 microug L(-1) Irgarol vs. > 200 microg L(-1) M1; S. costatum, 0.29 microg L(-1) Irgarol vs. 11.32 microg L(-1)M1; and T. pseudonana, 0.41 microg L(-1) Irgarol vs. 16.50 microg L(-1)M1). Secondly, we conducted a meta-analysis of currently available data on toxicities of Irgarol and M1 to both freshwater and marine primary producers based on species sensitivity distributions (SSDs). Interestingly, freshwater autotrophs are more sensitive to Irgarol than their marine counterparts. For marine autotrophs, microalgae are generally more sensitive to Irgarol than macroalgae and cyanobacteria. With very limited available data on M1 (i.e. five species), M1 might be less toxic than Irgarol; nonetheless this finding warrants further confirmation with additional data on other autotrophic species. 相似文献
5.
Vessels found contaminated with biofouling non-indigenous marine species are predominantly removed from the water and treated in vessel maintenance facilities (i.e., slipways, travel lifts and dry-docks). Using pre-fouled settlement plates to simulate a vessel’s removal from the water for treatment, we demonstrate that a range of mobile organisms (including non-indigenous marine species) may be lost to the marine environment as a consequence of this process. We also determined that different levels of biofouling (primary, secondary and tertiary) and emersion durations (0.5, 5 and 15 min) affected the abundance and composition of mobile taxa lost to the marine environment. Primary biofouling plates lost 3.2% of total animals, secondary plates lost 19.8% and tertiary plates lost 8.2%, while hanging duration had only minor effects. The results suggest that removing vessels contaminated with biofouling non-indigenous marine species from the water for treatment may not be as biosecure as is currently recognised. 相似文献
6.
Shipping represents a threat as a vector for the transfer of non-indigenous marine species through the discharge of ballast water and biofouling of vessels’ external structures and internal piping. While considerable attention has been given to the management of ballast water, there currently exists no international legal instrument with which to control biofouling.A number of existing legal mechanisms may be applicable in the context of coastal States’ rights under international law. However, existing mechanisms are insufficient to regulate all aspects of the biofouling problem to ensure comprehensive management of the issue. There is, therefore, a need for the development of a comprehensive international agreement to address this gap. The issue of biofouling on international vessels has now been included on the work programme of the International Maritime Organisation (IMO). As a contribution to discussions on how to address this particular issue at an international level, this article provides an analysis of the options available through the IMO to address this issue.Having defined the specific “threat scenario” with regard to hull fouling, the article will consider: (i) the international legal framework that has been established to regulate the harmful impacts of international shipping; (ii) the range of practical measures that are available to manage biofouling on vessels; and (iii) international legal options available to States to address the threat of biofouling posed by international shipping. 相似文献
7.
厦门港试验浮筏污损生物的群落 总被引：6，自引：1，他引：6
1989年6月至1990年5月在厦门港防污、防锈试验的浮筏群进行了周年的污损生物挂板。记录了90种生物,其中网纹藤壶、泥藤壶、僧帽牡蛎、翡翠贻贝、中胚花筒螅、太平洋侧花海葵、厦门膜孔苔虫和多种端足类是优势种。全年都有生物附着,夏、秋和冬、春季的优势种有显著的不同。附着量较大,夏季3个月的湿重生物量高达22.7kg/m~2。这个结果可为防污、防锈试验提供较确切的生物学依据。 相似文献
8.
Zongguo Huang 《海洋学报(英文版)》2003,22(3):467-482
From 1980 to 1998, biofouling communities in Hong Kong waters, the Zhujiang RiverEstuary and the Mirs Bay were studied and a total of 610 samples. The samples were collected from vessels, buoys, piers and cages. Totally, 340 species (see Appendix I ) have been recorded and identified, six of which are new. At the same time, research on the biology of the cirripede, bryozoan, polychaete and mollusc communities were also conducted. Twenty-three related papers have been published. This review summarizes works in Hong Kong over past twenty years, and some unpublished data are also reported. 相似文献
9.
This study presents an analysis of a wave energy converter (WEC) system consisting of a buoy, a mooring system, and a power cable connected to a hub. The investigated WEC system is currently under full-scale testing near Runde in Norway. The purpose of the study was to investigate the characteristics of the entire system, primarily with regard to energy performance and the fatigue life of the mooring lines and power cable, considering the effects of marine biofouling and its growth on the system’s components. By means of parametric study, the energy performance and fatigue life of the mooring lines and power cable were investigated considering two mooring configurations, three biofouling conditions, four sea states in a scatter diagram, and three wave and current directions. Hydrodynamic and structural response simulations were conducted in a coupled response analysis using the DNV-GL software SESAM. Energy performance analyses and stress-based rainflow counting fatigue calculations were performed separately using an in-house code. The results show that, for a WEC system which has been deployed for 25 years, biofouling can reduce the total power absorption by up to 10% and decrease the fatigue life of the mooring lines by approximately 20%. 相似文献
10.