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PENGARUH ARAH SAYAP PELIMPAH SAMPING DAN KEDALAMAN ALIRAN TERHADAP KOEFISIEN DEBIT
No full textSide weir is a type of protection structure which function is to protect channels from damage caused by excessive amount of water (overtopping) so the water level in channels or rivers is to be preserved. The type is spatially varied flow with decrease of discharge occurs in main channels along the side weir. Usually design of spillway applies entrance of slope 900. Thus this reduces discharge coefficient. In this research, the influence entrance slope less than 900 was observed such as 600 and 300. The observation showed that discharge coefficient is function of entrance slope and ratio value of water depth to weir radius (h/r) with largest discharge coefficient around value (0.341 – 0.366) with entrance slope value (55.850 – 57.730).
Abstract in Bahasa Indonesia :
Pelimpah Samping (side weir) adalah bangunan untuk melindungi saluran dari kerusakan yang diakibatkan oleh jumlah air yang berlebihan (overtopping). Dengan dipasang pelimpah samping maka ketinggian air di saluran atau sungai tetap terjaga. Tipe aliran adalah aliran berubah lambat laun terhadap ruang (spatially varied flow) dengan penurunan debit yang terjadi di saluran utama sepanjang pelimpah. Selama ini pembangunan pelimpah samping menggunakan sudut masuk 900 terhadap aliran utama. Dengan demikian mempunyai kerugian yakni berkurangnya koefisien pengaliran. Dilain pihak asumsi koefisien pengaliran tersebut sampai sekarang tetap dianggap cukup besar. Pada penelitian ini diamati pengaruh sudut masuk sayap yang lebih kecil dari 900 yaitu sudut 600 dan 300. Hasil penelitian menunjukkan bahwa koefisien debit merupakan fungsi dari sudut masuk dan nilai perbandingan kedalaman air dan jari-jari pelimpah (h/r). Koefisien debit terbesar bernilai antara (0,341 – 0,366) pada sudut masuk antara (55,850- 57,730)
Kajian Hubungan Antara Debit Berubah dengan Tinggi Muka Air dan Kecepatan Aliran
Get PDFAbstrak. Banjir merupakan bencana alam yang perlu perhatian serius agar dampak yang diakibatkan dapat diminimalkan. Pada kejadian banjir terjadi suatu fenomena dimana debit, tinggi muka air dan kecepatan aliran mencapai nilai maksimum pada waktu yang tidak bersamaan. Penelitian ini ditujukan untuk membuktikan dan memperlihatkan fenomena tersebut dengan membuat suatu pemodelan aliran tak tunak pada flume di Laboratorium Uji Model Fisik Hidraulik, Fakultas Teknik Sipil dan Lingkungan Institut Teknologi Bandung. Selain pemodelan fisik, untuk mendukung penelitian ini dilakukan pula pemodelan numerik satu dimensi dengan syarat batas yang didapat dari hasil pemodelan fisik. Dari hasil pemodelan fisik maupun numerik diperoleh bahwa kecepatan aliran mencapai nilai maksimum terlebih dahulu, kemudian debit mencapai nilai maksimum dan tinggi muka air mencapai nilai maksimum terakhir. Dan hasil pemodelan numerik satu dimensi tidak jauh berbeda nilainya dengan hasil pemodelan fisik. Pemodelan numerik satu dimensi tidak hanya dilakukan untuk penampang berbentuk persegi panjang saja, pemodelan juga dilakukan untuk saluran dengan penampang berbentuk trapesium dengan kemiringan z = 1 dan z = 2. Hal ini dilakukan untuk melihat efek dari perbedaan bentuk penampang saluran. Dengan syarat batas, kekasaran saluran dan lebar dasar saluran yang sama didapatkan debit pada saluran berpenampang trapesium dengan z = 2 lebih besar dibandingkan dengan saluran berpenampang trapesium dengan z =1 dan saluran berpenampang persegi panjang. Hal ini disebabkan karena pada saluran berpenampang trapesium dengan z = 2 memiliki luas penampang basah yang lebih besar dibandingkan saluran berpenampang trapesium dengan z = 1 dan saluran berpenampang persegi panjang,mengingat debit adalah fungsi dari kecepatan aliran dan luas penampang basah. Abstract. Flood is a natural disaster needs a serious attention to minimize its negative impact. When flood occurs, a phenomenon happens where discharge, water level and stream velocity reach the maximum value at the different time. This research is conducted to prove and show the phenomenon by constructing an unsteady flow model in a The Hydraulic Laboratory, Civil and Environment Engineering Department. To support this research, besides physical model, one dimension numerical model is also being used as a boundary condition from the result of physical model. The result of physical and numerical model is that the stream velocity reaches the maximum point earlier, then the discharge reaches the maximum point and the water level reaches the last maximum point.The result of one dimension numerical model has similar value with the physical model. The one dimension numerical model is not only done for the rectangular shape, but also for the trapezium shape channel with inclination z = 1 and z = 2. It is done to see the effect of the different between channel shapes. With identical boundary condition of the roughness coefficient and width of the bottom channel, the discharge of the trapezium shape channel with inclination z = 2 is larger than the discharge of the trapezium shape channel with inclination z = 1 and the discharge of the rectangular shape channel. It is caused by the trapezium shape channel with inclination z = 2 that has larger wetted area compared to the trapezium shape channel with inclination z = 1 and the rectangular shape channel considering discharge is the function of stream velocity and wetted area
Kajian Koefisien Limpasan Hujan Cekungan Kecil Berdasarkan Model Infiltasi Empirik untuk DAS Bagian Hulu (Kasus pada Cekungan Kecil Cikumutuk DAS Cimanuk Hulu)
Get PDFAbstrak. Infiltrasi kumulatif dihitung oleh F(f) = f(t).t. Laju infiltrasi (f(t)) merupakan fungsi kelembaban tanah awal (2); kandungan pori drainase cepat dan drainase lambat (0c dan 0l); serta durasi dan probabilitas hujan (t dan p). Nilai F(t) (mm) semakin besar dengan bertambahnya waktu hujan dan semakin kecilnya probabilitas hujan. Nilai ini berkisar antara 1,59 "“ 20,50 untuk lahan palawija; 1,88 "“ 21,23 untuk lahan agroforestri; 1,36 "“ 17,84 untuk lahan tidak digarap; 1,11 "“ 23,88 untuk lahan kayu campuran; dan 1,28 "“ 22,59 untuk lahan permukiman. Koefisien limpasan riil cekungan (C); merupakan perbandingan antara limpasan hujan empirik (ROempirik) dengan limpasan hujan model (ROC). Koefisien C model cekungan kecil (CM) diformulasi sebagai fungsi dari t dan p. dengan H = (9,16 + 6,61.t). Pada hujan rendah (< 4 mm), nilai CM adalah kecil (< 0.30). Pada hujan lebih besar (> 6 - 24 mm), nilai CMlebih tinggi (≥ 0.30 "“ 0.60). Pada hujan > 24 mm, nilai CM cenderung menuju konstan. Nilai (1"“CM) menunjukkan proporsi air dari ROC yang tersimpan pada cekungan kecil dalam bentuk intersepsi oleh tumbuhan; tertahan oleh ledok, tampungan kecil, atau reservoir-reservoir buatan, baik di permukaan maupun di dalam tanah. Simpanan ini, sekitar 40 % dari ROC.Abstract. Cumulative infiltrate calculated by F(t)= f(t).t. Rate of infiltrate (f(t)) is function of initial soil moisture (2), content of rapid and slow drainage pores ( ηc and ηl); and duration and probability of rain (t and p). Value of F (t) (mm) ever greater by increasing rain duration and smaller rain probability. This value range from 1,59 - 20,50 for the second crops; 1,88 - 21,23 for the agro forestry; 1,36 - 17,84 for the non arable land; 1,11 - 23,88 for the forest; and 1,28 - 22,59 for the settlement. The real runoff coefficient of small basin (C) is comparison between empirical run off (ROempirik) with the model run off (ROC). The Coefficient C model (CM) had formulated as with H = (9,16 + 6,61.t). At low rainfall (< 4 mm), the CM is small (< 0.30); at bigger rainfall (> 6 - 24 mm) the value of CM is higher (0.30 - 0.60); and at rainfall > 24 mm CM is tend to go constantly. The value of (1-CM) indicate proportion of ROC which storage in the forms interception by plant, micro basin on the land surface, or artificial reservoirs. That is around 40 % of ROC
PENGARUH ARAH SAYAP PELIMPAH SAMPING DAN KEDALAMAN ALIRAN TERHADAP KOEFISIEN DEBIT
Get PDFSide weir is a type of protection structure which function is to protect channels from damage caused by excessive amount of water (overtopping) so the water level in channels or rivers is to be preserved. The type is spatially varied flow with decrease of discharge occurs in main channels along the side weir. Usually design of spillway applies entrance of slope 900. Thus this reduces discharge coefficient. In this research, the influence entrance slope less than 900 was observed such as 600 and 300. The observation showed that discharge coefficient is function of entrance slope and ratio value of water depth to weir radius (h/r) with largest discharge coefficient around value (0.341 â 0.366) with entrance slope value (55.850 â 57.730). Abstract in Bahasa Indonesia : Pelimpah Samping (side weir) adalah bangunan untuk melindungi saluran dari kerusakan yang diakibatkan oleh jumlah air yang berlebihan (overtopping). Dengan dipasang pelimpah samping maka ketinggian air di saluran atau sungai tetap terjaga. Tipe aliran adalah aliran berubah lambat laun terhadap ruang (spatially varied flow) dengan penurunan debit yang terjadi di saluran utama sepanjang pelimpah. Selama ini pembangunan pelimpah samping menggunakan sudut masuk 900 terhadap aliran utama. Dengan demikian mempunyai kerugian yakni berkurangnya koefisien pengaliran. Dilain pihak asumsi koefisien pengaliran tersebut sampai sekarang tetap dianggap cukup besar. Pada penelitian ini diamati pengaruh sudut masuk sayap yang lebih kecil dari 900 yaitu sudut 600 dan 300. Hasil penelitian menunjukkan bahwa koefisien debit merupakan fungsi dari sudut masuk dan nilai perbandingan kedalaman air dan jari-jari pelimpah (h/r). Koefisien debit terbesar bernilai antara (0,341 â 0,366) pada sudut masuk antara (55,850- 57,730)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Analisis Pilar Modernisasi Irigasi dengan Pendekatan Analytical Hierarchy Process (AHP) pada Daerah Irigasi Barugbug - Jawa Barat
Get PDFAbstrak. Daerah irigasi Barugbug di Jawa Barat adalah daerah irigasi yang akan dijadikan sebagai contoh penerapan modernisasi irigasi. Pengertian dari modernisasi irigasi adalah suatu upaya untuk melakukan perubahan sistem pengembangan dan pengelolaan irigasi menjadi sistem irigasi partisipatif yang lebih efektif, efisien, dan berkesinambungan (sus-tainable). Pemahaman tentang pilar modernisasi dilakukan dengan survey terhadap responden petugas OP irigasi, petani P3A dan instansi pengelola irigasi Barugbug yang terdiri dari BBWS Citarum, SKPD TPOP Dinas PSDA Jawa Barat dan Perum Jasa Tirta II. Analisis deskriptif statistik seputar pengetahuan dan pemahaman responden terhadap penerapan pilar modernisasi irigasi dilakukan dengan Analytical Hierarchy Process (AHP) untuk mendapatkan urutan skala prioritas penerapan pilar modernisasi irigasi di Barugbug. Hasil dari Analitycal Hierarchy Process (AHP) didapatkan urutan prioritas penerapan pilar modernisasi Irigasi di Barugbug dengan hasil sebagai berikut : Urutan 1 : Pilar Ketersediaan Air Irigasi, Urutan 2 : Pilar SDM Pengelola Irigasi, Urutan 3 : Pilar Prasarana Irigasi, Urutan 4 : Pilar Sistem Pengelolaan Irigasi, Urutan 5 : Pilar Penguatan Lembaga Pengelola Irigasi.Abstract. Barugbug Irrigation Area in West Java is the irrigation area which will serve as an pilot project of the application of irrigation modernization. Irrigation modernization can be interpreted as an attemption to make changes to the development and management participatory irrigation system become effective, efficient, and sustainable. An understanding of the pillars of modernization carried out by survey respondents OP officer irrigation, P3A farmers and management of Barugbug Irrigation (BBWS Citarum, SKPD TPOP and Perum Jasa Tirta II). Descriptive Statistical Analysis of knowledge and understanding of each respondent to the application of irrigation modernization pillar then was done by Analytical Hierarchy Process (AHP) to get the priority scale order of the application of the pillars of modernization in Barugbug. The results of Analytical Hierarchy Process (AHP) obtain the order of priority in the application pillar of irrigation modernization in Barugbug with the following result are: Sequence 1: Pillars of Irrigation Water Availability, Sequence 2: Pillars of Irrigation Human Resources business, Sequence 3: Pillars of Irrigation Infrastructure, Sequence 4: Pillars of Irrigation Management System, and Sequence 5:Pillars of Strengthening Irrigation Management Institute
HIGH FLOW AND LOW FLOW FREQUENCY ANALYSIS OF CIKAPUNDUNG RIVER
Get PDFClimate change that occurs in Indonesia, especially in the upstream and middle Citarum areas is marked by changes in rainfall. In addition to the phenomenon of climate change, an increase in the number of people that occur in an area will have an impact on land cover changes that will affect river flow, so the dominant parameters that cause changes in the flow between changes in rainfall and land cover changes need to be reviewed. This study aims to determine the effect of changes in rainfall and land cover changes on flood discharge and the shift of flow duration curve. The author chose 4 SUH methods, namely SUH Nakayasu, SUH Soil Conservation Service (SCS), SUH ITB-1 and SUH Snyder-Alexejev to analyze high flow, and 2 methods, namely the F.J. Mock and NRECA methods to analyze low flow. The results of the research analysis are land changes that occur does not have a major impact on changes in the value of runoff coefficient, flood discharge analysis for Cikapundung-Pasirluyu sub-watersheds found that changes in flood discharge are dominated by changes in rainfall
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