著者
加藤 琢磨 手計 太一 土屋 修一 山田 正
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.52, pp.277-282, 2008 (Released:2010-08-25)
参考文献数
7

We carry out the microclimate field observation collaborated closely with local residents in the downtown of Tokyo in order to study the effect of watering on urban climatic environment. Local residents sprinkled recycled water which was rainfall and/or bath water in summer. Then we measured air temperature, humidity, solar radiation, aerosol number, wind velocity and wind direction all the day. We could observe atmospheric phenomena before/after watering. The following conclusions were obtained: 1) Air temperature at almost all observation stations were started to decrease immediately after watering started. Area-averaged air temperature declined by 0.5 deg. C. After Watering, it took an average time of 60 minitues to relapse to the air temperature immediately before the sprinkling. 2) Surface temperature of roadway decreased from 50 deg. C to 40 deg. C compared between before and after Watering. Assuming the surface of roadway could be black body, long-wave radiation declined from 620 W/m^2 to 510 W/m^2 compared between before and after watering. Heat environment mitigation action by watering could be divided into “fall of air temperature” and “restraint of radiation”.
著者
狩野 学 手計 太一 木内 豪 榊 茂之 山田 正
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.48, pp.193-198, 2004-02-01 (Released:2010-06-04)
参考文献数
8
被引用文献数
1 2

The large-scale social experiment, which many citizens including media representative participated for evaluating the effects of the watering on the “Heat Island Effect”, was carried out in Tokyo Metropolitan in Aug. 25 2003. About 14000l. water were sprinkled for about 20 minutes from noon. Air temperature and humidity were measured by moving observation system and fixed observation system at watering area in Eastern Tokyo. After the watering, the air temperature difference between outside and inside of watering area increases, and its difference was about 0.5°C. Temperature of watering area is lower than the temperature of outside area of watering after the watering. The effect of the watering was verified using the numerical simulation based on MM5. As a result of this analysis, air temperature degreased 2-2.5°C in watering area after the watering.
著者
前野 詩朗
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.51, pp.613-618, 2007 (Released:2010-08-25)
参考文献数
3

The rising backwater, which occurs due to the confluence of the Takahashi River and the Oda River, makes the water level rather higher during flood in the upstream of those rivers. The higher water level endangers embankments of those rivers. One of the possible means to reduce the water level is to relocate the present confluence site with the Oda River to the downstream site of the Takahashi River. This study aims to investigate the effect of the relocation of the confluence site using two-dimensional flow analysis. Numerical results under present river course condition were compared with the measured water level, and the effectiveness of the proposed analytical model was confirmed. It is also shown that the relocation of the confluence site has an effect to reduce the water levels of rivers considerably.
著者
土屋 修一 加藤 拓磨 手計 太一 山田 正
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.367-372, 2005-02-01 (Released:2011-06-27)
参考文献数
6

The social experiment was carried out for the purpose of the mitigation of the heat island effect by watering on August 18th to 25th. The microclimate observation has been carried out at watering area in Eastern Tokyo. As the results, the effect of the watering on the thermal environment in urban area was evaluated as decreasing effect on temperature. The following results were obtained; 1) The temperature variation in the daytime is included to be different every site because of the dispersion of surface temperature. 2) The air temperature in the experiment area is from 2 to 9 [degree] higher than temperature in thermometer shelter by the effect of long radiation. 3) The temperature decrease instantaneously when watering starts. 4) The temperature decreases 0.66 [degree] on average, 1.93 [degree] on maximum after the watering. 5) Total amount of decreasing temperature is decreased linearly by the distance from the point of watering.
著者
石井 宏明 神田 学 森脇 亮 奥園 孝二
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.43, pp.233-238, 1999
被引用文献数
1

Field observation was performed on two islands located in Tokyo Bay to investigate the atmospheric environment over Tokyo Bay by using Radio Sonde, Dopper Sodar and airplane in summer 1998.<BR>The following results were obtained; 1) The atmospheric boundary layer (ABL) over Tokyo Bay was composed of multiple layers.Especially, it was composed of three layers on August 10. 2) These multiple layers were formed by the effect of various kinds of return flows from the land. The upper boundary layer about 1250-2000m over Tokyo Bay was hotter and drier than the one over the land. 3) The airplane observation suggests that the air pollutant might be more concentrated over Tokyo Bay rather than over the land due to the difference of the boundary layer structure.
著者
松本 大毅 広城 吉成 堤 敦 神野 健二 新井田 浩
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.127-132, 2005-02-01 (Released:2011-06-27)
参考文献数
11

Sayanokami spring water exists in the new campus of Kyushu University, which is located on the western part of Fukuoka City. This spring water is one of the important water resources for agriculture around the new campus area. The construction of the new campus started last June, 2000. In this study, to understand the hydrological properties of the Sayanokami circumference, 222Rn and tritium were used as tracers, respectively. Consequently, it was found out that the residence time of Sayanokami spring water is 10-20 years. Moreover, the residence time and the catchment area of Sayanokami spring water were estimated using groundwater flow model. As a result, the residence time of Sayanokami spring water was evaluated to be about 25 years at most and the catchment area was specified. It is concluded that the accuracy of estimation of residence time and catchment area of the spring water can be improved by analysis of radioactive isotopes and groundwater flow model.
著者
松永 信博 増田 壮佑 中牟田 大嗣 徳永 貴久 矢野 真一郎 押川 英夫 橋本 彰博 藤田 和夫 古賀 雅之 岩下 智明 原田 敦彦
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.51, pp.1415-1420, 2007 (Released:2010-08-25)
参考文献数
11

Laboratory experiments were carried out on water quality purification by a porous concrete block including Bacillus subtilis natto group. The block is called EcoBio-Block (EBB). The time variations of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were obtained experimentally under the aerated condition by changing the weight ratio of EBB to water. The time variations of BOD and COD were expressed universally by normalizing the data. The reduction rate of BOD increases with the weight ratio. On the other hand, that of COD takes the maximum value at the weight ratio of 0.01 and decreases after that. The rapid reduction of BOD and COD seen in the early stage may be due to the adhesion or adsorption of organic matter by EBB. The mineralization of organic matter and the nitrification of NH4-N by EBB become active at the later stage and the activity increases with the weight ratio. It was experimentally revealed that EBB has also the very high ability for the water quality purification in the DO-saturated water and it depends strongly on the weight ratio of EBB to water.
著者
木内 豪 神田 学 栗城 稔 小林 裕明
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.38, pp.381-386, 1994-02-28 (Released:2010-08-25)
参考文献数
4
被引用文献数
2 2

Growing cities have been deteriorating heat environment due to artificial coverage of the ground and artificial heat effluence. The authors focused on the watering on paved roads as one of elective and immediate measures against the situation and observed the elect on the micro climate in a city area in the last summer. The results showed that the difference in temperature and humidity at two points with and without watering were maximum 1.5 degree and 8%, respectively. In addition, the estimated heat balance at the points showed that the considerable latent heat and the lateral heat transport contributed to lower the surface temperature of the road due to watering.
著者
芝 定孝 平田 雄志 八木 俊策
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.43, pp.245-250, 1999-02-10 (Released:2010-08-25)
参考文献数
10

Cloud droplet formation is an important process in water cycle between the earth and the atmosphere. In order to investigate the nonsteady growth of cloud droplets due to the condensation of the atmopheric water vapor on (NH4) 2 SO4 particles, a mathematical model has been constructed and the nonsteady growth has been simulated numerically with use of the mathematical model. The mathematical model is constituted by the conservation laws of water mass and heat energy and the state equation of ideal gas. As the speed of time variation of droplet heat QW is very fast compared with that of droplet mass mw, droplet temperature Ta can be treated as in steady state. The equilibrium droplet size ae is dependent on the 3/2 power of the initial radius aso of cloud condensation nucleus (NH4) 2SO4. The larger as0 is, the more the droplet grows in its equilibrium size ae. It takes much time for large condensation nucleus to attain the equilibrium size ae. It also has been cleared that Kelvin's equation is not always applicable to estimate the cloud droplet siz
著者
大成 博文 前田 邦男 松尾 克美 山原 康嗣 渡辺 勝利 石川 並木
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.46, pp.1163-1168, 2002-02-10 (Released:2010-06-04)
参考文献数
6
被引用文献数
2 3

New techniques for oyster cultivation at Hiroshima bay are investigated using sea water micro-bubbles.The present results indicate some new aspects that the device of sea water micro-bubble generated about 51/min air discharge. under the water depth of 10-15m. By generating micro-bubbles, the salinity of sea water in the surface layer increased about 13% and the water temperature decreased about 2°C in the oyster farm in summer. Finally, the oysters which had been named “Waka” about thirty years ago were restored to the original state by using sea water micro-bubble technique.“Waka oyster” grew up rapidly for about a half year and had a rich constituent of glycogen.
著者
Fumihito IETSUKA Akira WADA
出版者
Japan Society of Civil Engineers
雑誌
PROCEEDINGS OF HYDRAULIC ENGINEERING (ISSN:09167374)
巻号頁・発行日
vol.52, pp.1063-1068, 2008 (Released:2010-08-25)
参考文献数
8

We assumed two-dimensional advection-diffusion equation to be a basic equation and aimed to inspect the applicability of CIP method with tangent conversion through two benchmark problems. On the Skew Flow problem, we got superior results that CIP method with tangent conversion could catch a discontinuous border sharply without causing numerical oscillation. On the other hand, on the Rotating Cone problem, we got good results on the short time simulation but in the case of long time rotating cone velocity field CIP method with tangent conversion could not reproduce initial profile, so the room of improvement of the scheme is left.
著者
Masaharu FUJITA Yoshifumi SATOFUKA Shinji EGASHIRA
出版者
Japan Society of Civil Engineers
雑誌
PROCEEDINGS OF HYDRAULIC ENGINEERING (ISSN:09167374)
巻号頁・発行日
vol.50, pp.1003-1008, 2006 (Released:2010-08-25)
参考文献数
2

So far huge sediment production due to the eruption of Mt.Kelud has given serious damage to the Brantas river basin. On the other hand the eruption has provided soil and sand for agricultural land and construction material. So, as a first step to establishing an advanced control system both of the sediment runoff and the sediment utilization, we have investigated the change of sediment transport properties after the eruption in 1990. The field survey result shows that the sever sediment deposition occurred immediately after the eruption, but 1 year after the eruption the bed aggradation changed into the bed degradation because of active sand mining. Also we obtained the sediment supply condition at the confluences with the tributaries after the eruption and presented a way to estimate the condition. Furthermore the field observation result on wash load indicates the wash load transport rate decreased rapidly after the eruption.
著者
後藤 仁志 林 稔 安藤 怜 酒井 哲郎
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.47, pp.547-552, 2003-02-10 (Released:2010-06-04)
参考文献数
11
被引用文献数
1 3

The Lagrangian model of solid-liquid two phase flow is proposed by combining the Moving Particle Semi-implicit (=MPS) method with the Distinct Element Method (=DEM). The governing equations of two fluid model is discretized by the MPS method, with the model of interparticle collision in solid phase based on the DEM. The relationships of present model with the previous Lagrangian model of a motion of single sediment particle and the non-Newtonian fluid model are discussed. The performance of the present model is investigated by simulating the dropping lump of mud into still water. By comparing the solutions of three models, such as the present model; the two fluid model by the MPS method without the DEM; and the MPS method with the passively moving solids module, the effect of cohesion of mud is reproduced well by the present model.
著者
天羽 誠二 中野 晋 木村 剛士 津川 茂
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.52, pp.1393-1398, 2008

We investigated the real-time forecast system of a storm surge to reduce its disaster. Typhoon properties such as central atmospheric pressure were forecasted before several hours by two methods. The one is forecasting by using neural network technique based on the past typhoon data and the other is utilization of typhoon forecast information by the Meteorological Agency. As a result of the comparison of both methods, it was found that the latter gave more correct forecast of typhoon properties. Based on the forecasting values of typhoon, we carried out the real-time forecasting of a storm surge and examined the practical utility of this system.
著者
渡辺 亮一 山崎 惟義 島谷 幸宏 河口 洋一 兼重 俊介 神尾 章記
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.52, pp.1153-1158, 2008 (Released:2010-08-25)
参考文献数
6

SAKUTA ditch is the oldest irrigation channel in Japan. The first description is described in the Japanese Chronicle of Japan that is the Japanese oldest history book. SAKUTA ditch is located in FUKUOKA Prefecture. In other words it is the very precious irrigation channel which continues being used for more than 1500 years. According to the field observation results performed in SAKUTA ditch, it becomes clear that 24 species of fishes are existed. In recent years, however, there have been increasing demands from local residents for the creation of the convenient irrigation channel.The objective of this study is to evaluate the fish habitat and to discuss the relationship between vegetation covered ration and physical environmental condition in SAKUTA ditch. The study results indicate that the density of fishes in channel is related to the vegetation covered ratio and the velocity distribution in the ditch. These results suggested that the water's edge structure and the vegetation covered ratio in channel are greatly influenced to fish habitat evaluation.
著者
野々村 敦子 森本 茂昭 河原 能久 野間 京二
出版者
土木学会
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.1147-1152, 2005-02
被引用文献数
3

Oxygen levels in eutrophic water bodies can become rapidly depleted at the presence of stable thermal stratification. The anoxic condition induces the release of nutrients and heavy metals from bottom sediments, leading to water quality problems. In Goten reservoir, we installed two sets of jet flow generator. One jet flow generator transports the water near free surface and eject it near the bottom while the other discharges pumped groundwater near the bottom. Field measurement has been carried out to understand the destratification process by the induced flow and the resultant changes in water quality. It is demonstrated that the jet flow generators accelerate the destratification process considerably and that the spatial distribution of water quality in a horizontal plane shows little difference during the process. It is also found that further improvement with the jet flow generators is necessary to increase more effectively the dissolved oxygen concentration near the bottom.