{"title":"ESTIMATION OF STABILITY PERFORMANCE OF EXISTING BREAKWATERS USING A RELIABILITY APPROACH AND PROPOSAL OF EFFECTIVE COUNTERMEASURES TO PREVENT FUTURE FAILURES","authors":"Hiroshi Takagi","doi":"10.2208/JSCEJB.65.246","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.246","url":null,"abstract":"既設防波堤を対象として，その安定性能を推定する手法を提案した．信頼性手法に基づく本手法を適用することで，防波堤被災リスクを定量的に評価することができる．被災の評価指標として，期待滑動量に加えて，新たに端趾部における被災を評価する期待超過頻度という概念を提案した．過去の被災事例に対して，本手法を適用した結果，被災の発生を妥当に再現することができた．また，被災および非被災時の合計40ケースの防波堤に対して検討を行ったところ，高波ピークの継続時間を2時間と仮定した場合，期待超過頻度が0.02∼0.04程度の範囲に被災と非被災を区別する境界が存在することが確認された．最後に，本手法を応用した防波堤の補強改修の評価フローを提案し，具体的な事例を通じて，改修に伴う安定性向上の評価や有効な改修策について検討を行った．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"317 1","pages":"246-258"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73890124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A method to measure two-dimensional vorticity fields was developed by combining MLS, the Moving Least Square method, with PTV. A velocity vector at a grid point is approximated with a pair of quadratic functions fitted to velocity vectors at particle positions estimated by PTV which randomly distributed around the grid point. The vorticity is calculated by differentiating the quadratic functions. A two-dimensional Gaussian weight function is employed for fitting. The size of the interrogation area is represented with the standard deviation of the weight function. The expression
{"title":"A PROPOSAL OF A VORTICITY ESTIMATION METHOD WITH MLS AND PTV AND ITS APPLIACATION TO FLOWS UNDER WIND WAVES","authors":"K. Takehara, T. Etoh","doi":"10.2208/JSCEJB.65.151","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.151","url":null,"abstract":"A method to measure two-dimensional vorticity fields was developed by combining MLS, the Moving Least Square method, with PTV. A velocity vector at a grid point is approximated with a pair of quadratic functions fitted to velocity vectors at particle positions estimated by PTV which randomly distributed around the grid point. The vorticity is calculated by differentiating the quadratic functions. A two-dimensional Gaussian weight function is employed for fitting. The size of the interrogation area is represented with the standard deviation of the weight function. The expression","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"23 1","pages":"151-165"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81181083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Koirala, K. Hadano, Kimihiko Nakano, K. Taneura
Dynamics model has been proposed for the float-counterweight type wave energy converter which takes into account the vertical and horizontal forces on the energy extracting float. The model consists of the equation of the generator, force balance at stationary free state, equation of the float motion in operation, and the equation for the driving pulley motion. Second order simultaneous differential equations for the vertical and horizontal displacement of the float have been obtained as the equations to be solved. Components of the flow force have been evaluated from the linear progressive wave theory. Examination of the model using the experimental data shows that the model underestimates the heaving and surge, overestimates the wire tension, and gives relatively good agreement to energy gain.
{"title":"DYNAMICS MODEL OF MOVABLE BODY-TYPE WAVE ENERGY CONVERTER CONSIDERING TWO DIMENSIONAL MOTIONS OF THE FLOAT","authors":"P. Koirala, K. Hadano, Kimihiko Nakano, K. Taneura","doi":"10.2208/JSCEJB.65.179","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.179","url":null,"abstract":"Dynamics model has been proposed for the float-counterweight type wave energy converter which takes into account the vertical and horizontal forces on the energy extracting float. The model consists of the equation of the generator, force balance at stationary free state, equation of the float motion in operation, and the equation for the driving pulley motion. Second order simultaneous differential equations for the vertical and horizontal displacement of the float have been obtained as the equations to be solved. Components of the flow force have been evaluated from the linear progressive wave theory. Examination of the model using the experimental data shows that the model underestimates the heaving and surge, overestimates the wire tension, and gives relatively good agreement to energy gain.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"73 1","pages":"179-189"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86815377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"IDENTIFICATION OF FLOOD-RELATED SEDIMENTARY FEATURES WITH NON-DESTRUCTIVE SUBSURFACE EXPLORATIONS","authors":"R. Azuma, H. Sekiguchi, T. Kamai","doi":"10.2208/JSCEJB.65.141","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.141","url":null,"abstract":"近年の洪水氾濫災害の頻発は現行の治水システムが持つ根本的な課題を浮き彫りにしている．将来型の氾濫原マネジメントを考えるうえに，旧河道や破堤地形などの水害地形を定量的に計測・評価し，地域の洪水特性を考慮した治水対策を実施することが望まれる．本研究では，歴史的に水害常襲地であった宇治川左岸高水敷（河口から43.0km付近）を重点調査域とし，非破壊物理探査法（比抵抗探査および表面波探査）による埋没水害地形の同定を試みた．その結果，高水敷下に埋没した旧河道や砂州等の特徴ある水害地形が検出できた．その特徴は，自動スウェーデン式サウンディング調査，および連続コア採取ボーリング調査・堆積相観察による実証とも調和的である．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"2 1","pages":"141-150"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84140804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"NEW PRACTICAL FORMULAS FOR WAVE TRANSMISSION COEFFICIENT OF LOW-CRESTED STRUCTURES AND THEIR APPLICATIONS TO FIELD SITES","authors":"Y. Goda, Hideki Yoshida, Kazuyoshi Hachisuka, Keiji Kuroki","doi":"10.2208/JSCEJB.65.56","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.56","url":null,"abstract":"干出型の離岸堤や没水型の人工リーフを総称する低天端堤については，これまで適切な波高伝達率の推定法が確立されていなかったが，内部透過波と乗り越え伝達波の両者のエネルギー合成の考え方に基づく新しい実用的推定法を取りまとめ，既往の各種実験851データの波高伝達率の実験値ならびに現地の低天端堤（糸魚川，湯河原，新潟西海岸）の観測値と照合し，新方式の適用性を確認した．天端拡幅による波高伝達率の低減も再現された． 波高伝達率を支配する主パラメータは天端高と入射波高の比であり，内部透過波については天端幅と内部構成材の有効径との比および天端幅と波長の比，乗り越え伝達波については天端幅と深海波長との比が副パラメータとなる．さらに，模型の縮尺効果についても論究した．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"45 1","pages":"56-69"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85341590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"ACCURACY DETERIORATION OF INFLOW AND OUTFLOW ESTIMATION AT SMALL DAM RESERVOIR DURING FLOOD PERIOD","authors":"Hiroyuki Suzuki, Atsushi Ochiai, Masashi Suga, Atsuko Mizoguchi","doi":"10.2208/JSCEJB.65.81","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.81","url":null,"abstract":"神通川の発電ダム群ではあるダムからの放流量が直下流での河川流量やダムの流入量とほぼ合致する水文状況にある．ところが，平成16年台風23号による神通川の既往最大出水の際に，これらのダム群であるダムからの放流量とその直下流での河川流量やダムの流入量との間に約3000m3/sの大きな不一致が報告された． 本研究ではダム下流の河川流量を基点とした流量の追跡・精査等によって，この不一致の要因が接近流速の増大が引き起こした洪水吐き放流量の算定誤差であることを確認した．一般的な洪水吐きからの放流量算定式は接近流速の影響を無視しているが，本研究によって特に小規模貯水池の管理では接近流速が一概に無視できないというダム管理上の新たな問題を示した．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"44 1","pages":"81-86"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89637299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"FISH BEHAVIOR ANALIYSIS THROUGH A FIELD EXPERIMENT BY USING ADVANCED TELEMETRY SYSTEM","authors":"M. Denda, Kunihiko Amano, T. Tsujimoto","doi":"10.2208/JSCEJB.65.1","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.1","url":null,"abstract":"","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"33 1","pages":"1-14"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81274519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"NEW STORAGE FUNCTION MODEL CONSIDERING URBAN RUNOFF PROCESS","authors":"Tadakatsu Takasaki, A. Kawamura, H. Amaguchi, K. Araki","doi":"10.2208/JSCEJB.65.217","DOIUrl":"https://doi.org/10.2208/JSCEJB.65.217","url":null,"abstract":"本論文は，高度に市街化が進行した都市中小河川における実時間洪水予測に適した集中型概念モデルの精度向上に向けて，合流式下水道による流域外への排水など都市特有の流出機構を考慮し，また全流出成分を概念的に組み込むことで有効雨量の算定や流出成分の分離作業が不要となる新たな都市貯留関数モデルを提案したものである．本提案モデルを，東京都の代表的都市中小河川である神田川上流域を対象に，近年観測された豪雨9イベントに適用し，観測ハイドログラフに対する再現性を検証した．その結果，従来の貯留関数モデルと比べパラメータ数は2つ多くなるものの，流出ハイドログラフの予測精度が格段に向上し，ピーク流量や総流出量を的確に捉えられること，他降雨イベントに対するパラメータの安定性や適応性が向上することを確認した．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"97 1","pages":"217-230"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80069824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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