动水域进行静水航速试验的测算方法

受条件限制,某些河道的静水航速实船测试不得不在动水域进行.由于动水域水面坡降的存在,船舶推力需克服坡降阻力而不能全部为航行提供动力,对水航速代替静水航速会造成一定偏差.通过在澜沧江动水域进行的静水航速实船测试试验,提出了阻力平衡法和阻力同比法以修正静水航速,两种修正方法结果差异不大,而阻力同比法更为简略.理论和实例分析表明,对水航速是否能代替静水航速取决于坡降阻力所占船舶推力比例的大小.

某小型水下装备的水动力学设计与分析

水下装备工作环境复杂,获取其复杂工况下的水动力学参数是进行结构设计的关键。以某小型水下装备为研究对象,采用计算流体动力学方法分析了其在静水域和动水域的水动力学参数。研究了水下装备在静水域工作时的航行速度、漂角和攻角等对其水动力学参数的影响规律;采用重叠网格方法获取水下装备在动水域工作时侧面来流对其水动力学参数的影响规律;加工制作了小型水下装备样机,根据计算结果进行了推进器的选型与布置,验证了水动力学设计与分析的可行性。

Computation of Ship Hydrodynamic Interaction Forces in Restricted Waters using Potential Theory

A computer code based on the double-body potential flow model and the classic source panel method has been developed to study various problems of hydrodynamic interaction between ships and other objects with solid boundaries including the seabed. A peculiarity of the proposed implementation is the application of the so-called ＂moving-patch＂ method for simulating steady boundaries of large extensions. The method is based on an assumption that at any moment just the part of the boundary （＂moving patch＂） which lies close to the interacting ship is significant for the near-field interaction. For a specific case of the fiat bottom, comparative computations were performed to determine optimal dimensions of the patch and of the constituting panels based on the trade-off between acceptable accuracy and reasonable efficiency. The method was applied to estimate the sway force on a ship hull moving obliquely across a dredged channel. The method was validated for a case of ship-to-ship interaction when tank data were available. This study also contains a description of a newly developed spline approximation algorithm necessary for creating consistent discretizations of ship hulls with various degrees of refinement.

Three new records of Lumbrineridae Schmarda,1861(Annelida:Polychaeta)species in China

Three species of Lumbrineridae, Helmutnerisflabellicola （Fage, 1936）, Lurnbrinerides dayi Perkins, 1979, and Ninoe japonica Imajima ＆ Higuchi, 1975, are reported from the material collected between 1959 and 1994 from the Yellow Sea, East China Sea, and South China Sea. These species are not previously recorded from Chinese waters. Systematic descriptions and morphological illustrations of the species are provided in this paper.

Water discharge variability of Changjiang(Yangtze) and Huanghe(Yellow) Rivers and its response to climatic changes

Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation （ENSO） and the Pacific Decadal Oscillation （PDO）, on the temporal variations of the annual water discharge at the Lijin station in the Huanghe （Yellow） River and at the Datong station in the Changjiang （Yangtze） River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis （EMD- MESA） method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers.

Evaluating the maneuverability of a new type of self-propelled barge

A new type of self-propelled barge was designed specifically for use on the Chishui River. This paper presents experimental results of its performance from tests in water of different depths,while bearing different loads. For test purposes,one of the best self-propelled barges from the Chishui River was used as a performance reference. The comparison showed that the new design has better maneuvering performance.

A Study on Conversion of Marine Diesel Engines Using Blended Palm Oil for Inland Waterway Vessels in Vietnam

The climate change and limitation of natural resources becomes main obstacle for the global economical development. So, the Vietnamese Government is very much concerned with reduction of harmful gas discharging from the inland-water way ships. To overcome the problems, there are many counter-measures proposed such as： renovation of machinery and equipment, using re-creative energy and so on. The author＇s idea is to find a suitable method which can be applied on board of the inland-water ships to reduce discharging toxic gas by using blended palm oil as alternative fuel for marine diesel engines. Due to some disadvantages of the bended palm oil in comparison with traditional DO （diesel oil）, such as： low freezing point, high viscosity, low stability of blended fue, therefore somehow, the blended palm oil must be made a ship directly on board. With this idea, the author has designed and made agitate mixing equipment working on-line with fuel supply system of a diesel engine. The mixing equipment, then, has been tested at shore-side laboratory as well as on board ships. The research results showed that the fuel mixture （palm oil-DO） made by this mixing equipment is fully usable to replace traditional DO for marine diesel engines installed on board ships of inland water way in Vietnam. The Vietnamese Government accepted the research results as prerequisite to devise specific and practical action plans to reduce the pollution from the inland water way ships in coming years.

Seasonal discharge and chemical flux variations of rivers flowing into the Bayhead canal of Durban Harbour, South Africa

The u Mhlatuzana, u Mbilo and a Manzimnyama river catchments located on the eastern seaboard of the Kwa Zulu-Natal province, South Africa, form the core of urbanization and industrialization, contributing the only natural freshwater inflows to the Bayhead Canal portion of the Durban Harbour. In this study, seasonal discharges and physico–chemical water properties were used to quantitatively determine the material mass transport capacity of the river systems on the basis of hydrographic inputs and chemical loading from the surrounding land use sectors.The mass transport of the total dissolved solids(TDS),ammonia(NH_4), phosphorous(P), aluminum(Al), calcium(Ca), copper(Cu), chromium(Cr), mercury(Hg), potassium(K), magnesium(Mg), sodium(Na), nickel(Ni), lead(Pb), sulphur(S) and vanadium(V) was determined for each river. Results indicated that land use, seasonality and river flow were significant determinants for the material loading in the rivers and the receiving port waters. The spatio-temporal distribution patterns of chemical fluxes indicated that industrial activity associated with the a Manzimnyama canal contributed the most, with regards to TDS, NH_4, Ca, K, Mg, Na, S and V, loading in both wet and dry seasons, as well as Al, Cu, Hg and Pb during the dry season. Similarly, industrial activity associated with the u Mbilo/u Mhlatuzana Canal at the lower reaches accounted for the highest P, Al, Cu and Pb fluxes in the wet season alone. Fluxes of these parameters are used to explain theobserved elemental concentrations and patterns of the receiving port waters of the Bayhead Canal.

Deformities in silver pomfret Pampus argenteus caught from Kuwait waters

During sampling for spawning stock of the silver pomfret,Pampus argenteus in Kuwait waters,a few seriously deformed individuals were captured.These individuals had been attacked and wounded,but had healed and survived.The fish body deformities are believed to be caused by predation attempts on silver pomfret by predators such as sharks,groupers,and croakers.

Spectral Characterization of Colored Dissolved Organic Matter for Productive Inland Waters and Its Source Analysis

This study examined the spatiotemporal dynamics of colored dissolved organic matter （CDOM） and spectral slope （S）, and further to analyze its sources in three productive water supplies （Eagle Creek, Geist and Morse reservoirs） from Indiana, USA. The re- sults showed that he absorption coefficient aCDOM（440） ranged from 0.37 m-1 to 3.93 m-1 with an average of 1.89 ± 0.76 m-1 （±SD） for the aggregated dataset, and S varied from 0.0048 nm -1 to 0.0239 nm-1 with an average of 0.0108 ±0.0040 nmI. A significant relation- ship between S and aCDOM（440） can be fitted with a power equation （S = 0.013 × aCDOM（440）-0.42, R2 = 0.612）, excluding data from Geist Reservoir during high flow （12 April 2010） and the Morse Reservoir on 25 June 2010 due to a T-storm achieves even higher determina- tion coefficient （R2 = 0.842）. Correlation analysis indicated that aCDOM（440） has strong association with inorganic suspended matter （ISM） concentration （0.231 〈 R2 〈 0.786） for each of the field surveys, and this trend followed the aggregated datasets （R2 = 0.447, p 〈 0.001）. In contrast, chlorophyll-a was only correlated with aCDOM（440） in summer and autumn （0.081 〈 R2 〈 0.763）, indicating that CDOM is mainly from terrigenous sources in early spring and that phytoplankton contributed during the algal blooming season. The S value was used to characterize CDOM origin. The results indicate that the CDOM source is mainly controlled by hydrological varia- tions, while phytoplankton originated organic matter also closely linked with CDOM dynamics in three productive reservoirs.

Effects of Roughness Elements Distribution on Overland Flow Resistance

Roughness elements are various in a mountain area; they include gravel and ground surface vegetation that often result in surface friction drag to resist overland flows. The variation and characteristics of flow resistance strongly impact the overland flow process and watershed floods. In view of the universal existence of natural vegetation, such as Chlorophytum malayense(CM) or Ophiopogon bodinieri(OB), and the sand-gravel bed of the river channel, it is important to understand the role of different types of roughness elements in flow resistance. This study was performed to investigate and compare through flume experiments the behaviors of overland flow resistance by the reaction of multi-scale configuration of different roughness elements. The result showed that the resistance coefficient gradually reduced versus the increase of flow rate in unit width and tended to be a constant when q = 3.0 l/s.m, Fr = 1.0, and Re = 4000 for slopes of 6 to 10 degrees. The gap of the vegetated rough bed and the gravel rough bed is limited to the same as the gap of the two types of vegetation, CM and OB. It was noted that the vegetation contributed to the increase in form resistance negatively and may lead to the mean resistance on decrease. To classify the flow pattern, the laminar flows were described by DarcyWeisbach's equation. In the study the f-Re equation of vegetated bed was developed with f ?5000 Re.The friction coefficient for laminar flows can be regarded as the critical value for identifying the transformation point of the flow pattern.

Hydrodynamic processes and depositional styles of glacierassociated deposits in the Moxi basin, Southwest China

This study aims to understand the particle size distribution and depositional styles of glacierassociated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated deposits(including glacial till,fluvioglacial, debris flow, river and lake deposits)were collected and tested in the laboratory. The results showed that the glacier-associated deposits can be differentiated based on particle gradation,particle size distribution and accumulated percentages. We evaluated the evolution of a former dammed lake in the Moxi basin based on glacierassociated deposits. The results of this study also indicated that the Moxi Platform was not formed by a single depositional process but is composed of both fluvioglacial and debris flow deposits. This research shows that the depositional style analysis is useful in identifying different glacier-associated deposits in high mountain regions. Moreover, the evaluation of the differences in particle sizes of the glacierassociated deposits is useful in reconstructing geohazard events in periglacial regions, and this information can help in identifying and reducing the potential risks associated with geo-hazards.

Drowned Early Mesolithic Landscapes on the Baltic Sea Bed in the Lithuanian Waters

This paper presents underwater relict forest fossil and ancient coast formation exploration results in the eastern Baltic Sea. Tree fossils and sediment layers discovered in the sea-bed were dated with 14^C along with palynological and dendrological analysis. Based on the obtained data, a fragment of submerged early Holocene landscape, coastline of the Yoldia Sea and Ancylus Lake has been reconstructed. The research data determine that vegetation and natural conditions of the Yoldia Sea coastal were favourable for Early Mesolithic communities. Well-preserved relict pine forest dates are also crucial to Baltic Sea water level dynamics analysis during the period： end of Yoldia Sea-Ancylus Lake.

Ecosystem health evaluation system of the water-fluctuating zone in the Three Gorges Area

This paper discribes the definition of ecosystem health for the water-level flutuation zone of the Three Gorges Region and puts forward an evaluation system involving indicators in three groups: 1) structural indicators comprise slope, biodiversity, environmental capacity, stability, restoration ability and damage situation; 2) functional indicators including probability of geological hazard, erosion rate, habitat rate, land use intension and days of tourist season; 3) environmental indicatiors made up of population quality, potential intension of human, ground water quality, ambient air quality, wastewater treatment rate, pesticide use rate, fertilizer use rate, environmental management and public participation. In the design of the system, the subject zone is regarded as the type similar to wetland and the impacts of human activities on the zone are attached great importance to.

Variability of subduction rates of the subtropical North Pacific mode waters

The climatology subduction rate for the entire Pacific is known, but the mechanism of interannual to decadal variation remains unclear. In this study, we calculated the annual subduction rates of three types of North Pacific subtropical mode waters using a general circulation model (LICOM1.0) for the period of 1958-2001. The model experiments focused on interannual variations of ocean dynamical processes under daily wind forcings and seasonal heat fluxes. The mode water formation region was defined by a potential vorticity minimum at outcrop locations. The model results show that two subduction rate maxima (>100 m/a) were located in the Subtropical Mode Water (STMW) and the Central Mode Water (CMW) formation regions. These regions are consistent with a climatologically calculated value. The subduction rate in the Eastern Subtropical Mode Water (ESTMW) formation region was smaller at about 75 m/a. The subduction rate shows clear interannual and decadal variations associated with oceanic dynamic variabilities. The average subduction rate of the STMW was much smaller during the period of 1981-1990 compared with other periods, while that of the CMW had a negative anomaly before 1975 and a positive anomaly after 1978. The variability agreed with Ekman and geostrophic advections and mixed layer depths. The interannual variability of the subduction rate for the ESTMW was smallest during 1970-1990, as a result of a weak wind stress curl. This paper explores how interannual signals from the atmosphere are stored in different parts of the ocean, and thus may contribute to a better understanding of feedback mechanisms for the Pacific Decadal Oscillation (PDO) event.

Three new records of deep-water goniasterids (Echinodermata:Asteroidea:Goniasteridae) from China seas

In this paper,three deep-water species of the family Goniasteridae,Ceramaster misakiensis(Goto,1914),Nymphaster arthrocnemis Fisher,1913 and Pontioceramus grandis Fisher,1911,are recorded for the first time from Chinese waters based on collections deposited in the Marine Biological Museum,Chinese Academy of Sciences.The specimens examined were collected during the period 1956 to 1978 from the East China and South China Seas at depths of 184 to 472 m.Diagnosis,detailed figures,and the geographic distributions are provided.A revised list of Goniasteridae recorded from Chinese waters is proposed.

Variation of Floods Characteristics and Their Responses to Climate and Human Activities in Poyang Lake, China

The Poyang Lake is one of the most frequently flooded areas in China. Understanding the changing characteristics of floods as well as the affecting factors is an important prerequisite of flood disaster prevention and mitigation. The present study identified the characteristics variations of historical floods in the Poyang Lake and their tendencies based on the Mann-Kendall(M-K) test, and also investigated the related affecting factors, both from climate and human activities. The results revealed that the highest flood stages, duration as well as hazard coefficient of floods showed a long-term increasing linear trend during the last 60 years with the M-K statistic of 1.49, 1.60 and 1.50, respectively. And, a slightly increasing linear trend in the timing of the highest stages indicated the floods occurred later and later during the last six decades. The rainfall during the flood season and subsequent discharges of the Changjiang(Yangtze) River and runoff from the Poyang Lake Basin were mainly responsible for the severe flood situation in the Poyang Lake in the 1990 s. In addition, the intensive human activities, including land reclamation and levee construction, also played a supplementary role in increasing severity of major floods. While, the fewer floods in the Poyang Lake after 2000 can be attributed to not only the less rainfall over the Poyang Lake Basin and low discharges of the Changjiang River during flood periods, but also the stronger influences of human activity which increased the floodwater storage of the Poyang Lake than before.

Slip Rate on the Altyn Tagh Fault on the West of the Cherchen River (Between 85°～ 85°45′E) Since Late Quaternary

Because of the significance to the formation and evolution of the Tibetan plateau, the displacement and slip rate of the Altyn Tagh fault have been topics full of disputation. Scientists who hold different opinions on the evolution of Tibet insist on different slip rates and displacements of the fault zone. In the article, study is focused on the late Quaternary slip rate of the Altyn Tagh fault west of the Cherchen River (between 85°E and 85°45’E). On the basis of high resolution SPOT images of the region, three sites, namely Koramlik, Aqqan pasture and Dalakuansay, were chosen for field investigation. To calculate the slip rate of the fault, displacement of terraces was measured on SPOT satellite images or in situ during fieldwork and thermo-luminescence (TL) dating method was used. To get the ages of terraces, samples of sand were collected from the uppermost sand beds that lie just under loess. The method for calculating slip rate of fault is to divide the displacement of terrace risers by the age of its neighboring lower terrace. The displacement of rivers is not considered in this article because of its uncertainties. At Koramlik, the slip rate of the Altyn Tagh fault is 11.6±2.6mm/a since 6.02±0.47ka B.P and 9.6±2.6mm/a since 15.76±1.19ka B.P. At Aqqan pasture, about 30km west of Koramlik, the slip rate is 12.1±1.9mm/a since 2.06±0.16 ka B.P. At Dalakuansayi, the slip rate of the fault is 12.2±3.0mm/a since 4.91±0.39ka B.P. Hence, we get the average slip rate of 11.4±2.5mm/a for the western part of the Altyn Tagh Fault since Holocene. This result is close to the latest results from GPS research.

Nutrient fluxes in the Changjiang River estuary and adjacent waters——a modified box model approach

To solve nutrient flux and budget among waters with distinct salinity difference for water-salt- nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the traditional way cannot cope appropriately with those without distinct salinity difference that parallel to coastline or in a complex current system, as the results would be highly affected by box division in time and space, such as the Changjiang （Yangtze） River estuary （CRE） and adjacent waters （30.75°-31.75°N, 122°10′-123°20′E）. Therefore, we developed a hydrodynamic box model based on the traditional way and the regional oceanic modeling system model （ROMS）. Using data from four cruises in 2005, horizontal, vertical and boundary nutrient fluxes were calculated in the hydrodynamic box model, in which flux fields and the major controlling factors were studied. Results show that the nutrient flux varied greatly in season and space. Water flux outweighs the nutrient concentration in horizontal flux, and upwelling flux outweighs upward diffusion flux in vertical direction （upwelling flux and upward diffusion flux regions overlap largely all the year）. Vertical flux in spring and summer are much greater than that in autumn and winter. The maximum vertical flux for DIP （dissolved inorganic phosphate） occurs in summer. Additional to the fluxes of the ChanNiang River discharge, coastal currents, the Taiwan Warm Current, and the upwelling, nutrient flux inflow from the southern Yellow Sea and outflow southward are found crucial to nutrient budgets of the study area. Horizontal nutrient flux is controlled by physical dilution and confined to coastal waters with a little into the open seas. The study area acts as a conveyer transferring nutrients from the Yellow Sea to the East China Sea in the whole year. In addition, vertical nutrient flux in spring and summer is a main source of DIP. Therefore, the hydrodynamic ROMS-based box model is superior to the traditional one in estimating nutrient fluxes in a complicated hydrodynamic current system and provides a modified box model approach to material flux research.

A Study of the Large Scale Flooding over Eastern China in 1755

Following disastrous flooding in several river valleys over eastern China in 1755, serious flooding occurred in the middle and lower reaches of the Yellow River in 1756 and 1757, a rarely seen precipitation pattern of north-flood and south-drought in China for two successive years. This is a serious meteorological disaster and extreme climatic event taking place under the climatic background of a warm phase of the Little Ice Age. In this paper, by means of historical literature records, the rainy and flooding situation and the weather characteristics of these years are reconstructed and the maps depicting areas of prolonged rain, flood and concomitant famine, insect pest, and pestilence are made. The results show that, in 1755, the middle and lower reaches of the Yellow River and the Yangtze River, and the Huaihe River Basin experienced a prolonged rainy season with multiple torrential rain events. The continuous rainy period exceeded 40 days in the Huang-Huai Region. An early Meiyu occurred, and the duration of the Meiyu period in the lower Yangtze River Basin was 43 days, the longest in the 18th century. Particularly in Nanjing the annual rainfall of 1755 was 1,378 mm, the highest record of the 18th century. The year of 1755 is characterized by lower temperature in summer, early frost in autumn, and heavy snowfall and freezing rain in winter. These characteristics are extremely similar to those of 1823 and 1954, two typical years of extreme rainfall. And all these three years with extreme precipitation axe corresponding to the minimum phase of the solar activity cycle.