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排序方式: 共有349条查询结果,搜索用时 15 毫秒
131.
132.
133.
Wells turbine with end plates for wave energy conversion 总被引:1,自引:0,他引:1
Manabu Takao Toshiaki Setoguchi Yoichi Kinoue Kenji Kaneko 《Ocean Engineering》2007,34(11-12):1790-1795
In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plate on the turbine characteristics has been investigated experimentally by model testing. As a result, it is found that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine, i.e., the turbine without end plate and the characteristics are dependent on the size and position of end plate. Furthermore, by using a computational fluid dynamics (CFD), reason of the performance improvement of the turbine has been clarified and the effectiveness of the end plate has been demonstrated. 相似文献
134.
Water motion is a very important environment surrounding marine organisms. It is, however, difficult to measure currents with a propeller type of current meters in seagrass or seaweed beds in shallow waters. Therefore, we elaborate the measuring method of time-averaged intensity of water motion with plaster balls invented by Muus (1968) to set them at several depths at short vertical intervals in shallow waters. Theoretical examination is also made on the relation between speed of steady flow and dissolution rate of plaster balls by experiments in a circuit tank. These experiments revealed that the temporal rate of decrease in the 1/2 power of wet weight of plaster balls excluding a rod supporting the plaster ball was proportional to the speed of steady flow in the tank. On the basis of this relation, we propose the method for estimating the time-averaged intensity of water motion by converting the loss of wet weight of plaster ball to the speed of steady flow bringing equivalent loss. Since this method is simple and convenient, it can be applied to obtaining environmental indices of water motion not only in seagrass or seaweed forests, but also in fishing grounds culturingporphyra, yellow tail (Seriola quinqueradiata) or oysters. 相似文献
135.
Hideo Kawai 《Journal of Oceanography》1987,43(3):204-215
For the audience or readers to deepen understanding of fisheries oceanography, especially physical fisheries oceanography, this lecture reviews my research work, including clues, failures and management problems encountered during the course of my studies. The contents of this lecture are: (1) introduction, (2) hydrographical feature in and around the Perturbed Area between the Kuroshio and Oyashio Fronts and its fluctuation, (3) conservative properties along a streamline or a trajectory and observation planning, (4) the Kuroshio south of Japan and warm and cold eddies pinched off from the Kuroshio meanders, (5) convergence-divergence of currents and accumulation-dispersal of marine organisms, (6) the Japan Sea (and a part of the East China Sea), and (7) conclusion: approaches to research in fisheries oceanography. 相似文献
136.
Hideo Kawai 《Journal of Oceanography》1986,42(1):30-38
An attempt is made to find a relation betweenK, the absolute value of accumulation-dispersal coefficient of marine organisms referred to a region or a group (Kawai, 1986a), andL, the square root of the area of the region or the group over which the distribution density of organisms is averaged.K is estimated as shown below. For appropriate sampling time-intervals,K becomes greater than other coefficients such as population growth coefficient. Using this result, an order of magnitude ofK dependent onL is estimated from various data of temporal change in density. With the aid of a dependenceQL
–2/3 (Kawai, 1985b), a relationKL
–2/3 is predicted for 30 cmL 30 km, whereQ andK are the root-mean-square values of area-averaged horizontal divergence of near-surface flows and of the accumulation-dispersal coefficient, respectively. The reason whyK tends to have the order of magnitude of weak or mediumQ is discussed. The doubling-halving time of the distribution density due to accumulation-dispersal,T, is related toK byT=(loge2)/¦K¦L
2/3. Finally, sampling time-intervals to estimate accumulation-dispersal coefficients are referred to. 相似文献
137.
Naoto Iwasaka Toshio Suga Kensuke Takeuchi Keisuke Mizuno Yasushi Takatsuki Kentaro Ando Taiyo Kobayashi Eitarou Oka Yasuko Ichikawa Motoki Miyazaki Hiroshi Matsuura Kenji Izawa Chan-Su Yang Nobuyuki Shikama Momoko Aoshima 《Journal of Oceanography》2003,59(1):119-127
We deployed two profiling floats in the region south of the Kuroshio Extension in March 2000. Temperature and salinity profiles
from a depth of 1500 × 104 Pa to the surface are reported every two and four weeks, respectively. The floats performed very well for first four months
after deployment. Later they failed in surfacing for a few months when the sea surface temperature in the region was high.
The salinity sensors seemed to suffer from some damage during their failure-in-surfacing period. Despite this trouble, the
results clearly demonstrate that the profiling float is a very useful and cost-effective tool for physical oceanographic observation
in the open sea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
138.
Jean M. Johnson Yuichiro Tanioka Kenji Satake Larry J. Ruff 《Pure and Applied Geophysics》1995,144(3-4):633-647
Two earthquakes occurred in 1993 off southern Kamchatka. They have similar surface wave magnitudes, focal mechanisms, and depths, but have distinctly different characteristics. The November earthquake is a standard or impulsiveM7 underthrusting event. The June earthquake is a tsunamigenic or low-stress-drop event with several unusual characteristics, including a large, diffuse aftershock zone, directivity, and a long source time function. The 1993 earthquakes ruptured a segment of the Kamchatka Arc which has not ruptured since 1904. The 1993 earthquakes seem to signal the midpoint in the southern Kamchatka seismic cycle. 相似文献
139.
The present study is a modification of the wave prediction model presented in the first paper of this title (Kawai
et al., 1979) based on the Toba's (1978) single parameter equation of the wind wave growth. The introduction of a grid method reduces
the two defects pointed out inKawai
et al., i.e., the absence of the prediction of certain instants at fixed points, and the concentration of wave energy at certain
points in the wind direction, arising from the lack of treatment of the lateral spreading of wave energy around the wind direction.
The new model is applied to the same set of data. The results shows overall improvements, such as the elimination of certain
overestimate in the first study and the coincidence of the predicted maximum with the measured one. The swells are separately
hindcasted and a very good agreement with measurement is obtained. 相似文献
140.
Robustness,uncertainties, and emergent constraints in the radiative responses of stratocumulus cloud regimes to future warming 总被引:1,自引:0,他引:1