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221.
222.
近岸海浪模式在中国东海台风浪模拟中的应用--数值模拟及物理过程研究 总被引:6,自引:2,他引:6
较为详细地介绍了基于能量平衡方程的第三代近岸海浪数值模式SWAN(Simulation Waves Nearshore)及其包含的物理过程(风生浪、底摩擦、白浪耗散、深度诱导波破碎、非线性波-波相作用等),并利用该模式对影响杭州湾-长江口沿岸海域的一次台风浪过程进行了模拟研究:模式所需风场由藤田台风风场模型嵌入对应台风特征等压线,并对相应时段的NCAR/NCEPT资料、单站资料进行同化后提供;利用自嵌套的方式提供波谱边界条件;模式模拟的结果与实际海浪观测资料相符较好,在此基础上,研究了底摩擦、深度诱导波破碎、三波相互作用等物理过程联合对近岸台风浪的影响,初步认识了它们在近岸台风浪生成、传播过程中的重要作用。 相似文献
223.
Fumio Horiguchi Kisaburo Nakata Naganori Ito Ken Okawa 《Estuarine, Coastal and Shelf Science》2006,70(4):589
A risk assessment of Tributyltin (TBT) in Tokyo Bay was conducted using the Margin of Exposure (MOE) method at the species level using the Japanese short-neck clam, Ruditapes philippinarum. The assessment endpoint was defined to protect R. philippinarum in Tokyo Bay from TBT (growth effects). A No Observed Effect Concentration (NOEC) for this species with respect to growth reduction induced by TBT was estimated from experimental results published in the scientific literature. Sources of TBT in this study were assumed to be commercial vessels in harbors and navigation routes. Concentrations of TBT in Tokyo Bay were estimated using a three-dimensional hydrodynamic model, an ecosystem model and a chemical fate model. MOEs for this species were estimated for the years 1990, 2000, and 2007. Estimated MOEs for R. philippinarum for 1990, 2000, and 2007 were approximately 1–3, 10, and 100, respectively, indicating a declining temporal trend in the probability of adverse growth effects.A simplified software package called RAMTB was developed by incorporating the chemical fate model and the databases of seasonal flow fields and distributions of organic substances (phytoplankton and detritus) in Tokyo Bay, simulated by the hydrodynamic and ecological model, respectively. 相似文献
224.
A comparison of two three-dimensional numerical modeling systems for tidal elevations and velocities in the coastal waters is presented. The two modeling systems are: (1) the Princeton Ocean Model (POM) and (2) the MIKE 3 flow model. The model performance results for Singapore's coastal waters show that the predicted tidal elevations from the two hydrodynamic modeling systems are almost identical and are in very good agreement with field measurement data. The simulated tidal current velocities match well with field measurement data at the selected stations, but it seems that the POM provides the slightly better simulation, compared to the MIKE 3 flow model. The depth profiles of the velocities obtained from the two modeling systems may be greatly different at some time, due to the vertical diffusion coefficient calculated from different turbulent sub-models in the two modeling systems. The POM generally predicts larger peak tidal velocities. The maximum speed differences for the model results from the two modeling systems occur in the top and differ from time to time and from location to location, reaching up to 20%. 相似文献
225.
Zhang Jinshan Yu Guohua
Research Engineer River Harbour Department Nanjing Hydraulic Research Institute Nanjing Research Senior Engineer River Harbour Department Nanjing Hydraulic Research Institute Nanjing 《中国海洋工程》1995,(3)
- Based on field investigations, this paper analyzes three types of harbour basinns and navigation channel excavated on seabed in Jiaozhou Bay, get a general rule of deposition for excavated trough, it found that pollution is one of crucial factors resulting in the deposition of the excavated trough in the east shore of Jiaozhou Bay. With these results, it predicted the annual deposition thickness for the excavated trough and disclosed the fact that it can't be deposited deadly during one storm. At the same time, with two-dimensional numerical model, it studied the effects of the excavated trough and the reclamation near shore on tidal cureent and said that the excavated trough can decrease the current velocity passing through the trough about 10- 15%, but only limited inside and near the trough and there are no effect on other regions; reclamation can cut off the pollution sources and no obvious effect on the currents of the Jiaozhou Bay. Connecting the deep trough and Cangkou tidal channel with a new 相似文献
226.
模型沙干重度在动床模型试验中是影响起动流速比尺和冲淤时间比尺的重要参数,其随淤积历时、粒径变化、埋置深浅和加工方法的不同有着不同的变化规律。通过试验,结合已有的成果,对模型沙干重度受以上几种因素的影响进行了研究,并进一步分析了其变化规律在动床模型试验中的作用。 相似文献
227.
From the phase-resolving improved Boussinesq equations (Beji and Nadaoka, Ocean Engineering 23 (1996) 691), a phase-averaged Boussinesq model for water waves is derived by more effectively describing carrier wave groups and accompanying long wave evolution with less CPU time. Linear shoaling characteristics of carrier wave equations are investigated and found to agree exactly with the analytical expression obtained from the constancy of energy flux for the improved Boussinesq equations themselves, showing that the present model equations are the results of a consistent derivation procedure regarding energy considerations. Numerical simulations of the derived equations for the single wave group and narrow-banded random waves show the validity of the present model and its high performance, especially on the CPU time. 相似文献
228.
礁膜配子放散条件的研究 总被引:2,自引:0,他引:2
本文报道了礁膜配子的放散与温度、光照、比重的关系。结果表明,自然海区的礁膜在白天大量放散配子。配子放散的适宜温度为19-21℃;光照为2000-5000lx时能促进配子大量放散出来;配子放散的适宜比重为1.05-1.025;这些研究结果将为礁膜人工育苗提供一些科学依据。 相似文献
229.
Most of the existing relevant materials have been obtained from experiments, in which evaluating the added mass at the resonant frequency corresponding to the peak of a frequency-response curve obtained from the “forced” vibration analysis is the most popular technique. In this paper, a simple experimental method was presented where the “free” vibration responses instead of the “forced” ones were used to determine the values of mah and Iap. The main part of the experimental system is composed of a floating body (model) and a spring–shaft shaker. The “free” vibration of this main part was induced by imposing on it an initial displacement (and/or an initial velocity), and from the time histories of displacements information such as the “damped” natural frequencies, damping ratios, sectional added mass coefficients (CV and CP) were obtained. Since the displacements of the spring–shaft shaker are “translational” and those of the floating body due to pitch motions are “angular”, a technique for the transformation between the associated parameters of the two components of the main part was presented. 相似文献
230.
1 .IntroductionThepenetratingbucketandboxfoundationisanewtypeofstructure ,whichhasbeenappliedinmanyengineeringfields .Inviewofthehighconstructioncostandtheformidableconstructibilityofoff shoreplatformswithpiledfoundations ,Baerheimetal.(1 990 )proposedtheconc… 相似文献