Civil Engineering

Scouring is one of many damages that water can cause. Scouring can occur as a consequence of bridge pile existence. The problem on local scour around single pier will be studied by using FVCOM numerical model. This study objective is to find out how accurate FVCOM model to predict local scour behavior. FVCOM model is based on the finite volume method to solve Navier Stokes, Meyer Peter Muller, and Exner equations. FVCOM computed numerical result then will be verified with computed and measured data in previous numerical (FSUM model) and experimental study. Results from this study show FVCOM model were successfully simulated typical features of local scour around piers such as downflow and wake vortex, but failed to simulate horseshoe vortex. Both computed numerical (FSUM and FVCOM) results are then compared with measured experimental data for its magnitude and time-series of maximum scour depth. FVCOM result shows value 0.99 r-squared correlation and 5.96 percent average error, and ...

In numerical modeling, dam break is one case that has its own challenges, because shock wave is found in the dam break modeling that usually provides a numerical instability. Usually, dam break problem is solved by Saint Venant equation using a finite difference method with artificial dissipation or Total Variation Diminishing (TVD) filter. But in this research, finite element method and the finite difference method are used. To verify the accuracy of the model, a comparison against the Stoker analytical method for dam break case was performed. Numerical modeling of dam break is required to find out the collapse area, thus it is used for determining mitigation that can be done in the area, related to dam safety. In numerical modeling, oscillation or numerical instability often occurs, for which special treatment is required to reduce or eliminate the oscillations. In this research, the treatment for that case is a Hansen filter for both methods. From the simulation result, it is fou...

Chute spillway merupakan desain pelimpah yang paling umum dan mendasar untuk mengalirkan kelebihan air pada tubuh bendungan/embung ke sungai di bawahnya melalui penurunan yang mulus. Tipe pelimpah ini cocok untuk melengkapi tubuh embung sederhana. Selain chute spillway, ada jenis pelimpah lain yang dapat dipertimbangkan sebagai alternatif untuk pembangunan di kawasan ini, yakni drop inlet. Drop inlet atau dikenal juga sebagai shaft spillway merupakan desain pelimpah yang alirannya masuk melalui sebuah bibir/celah horizontal, lalu jatuh melalui suatu lubang/cerobong vertikal, dan selanjutnya aliran tersebut akan dibawa melalui saluran atau terowongan mendatar. Drop inlet merupakan tipe pelimpah dengan kapasitas debit banjir kecil hingga sedang yang baik dibangun jika ruang yang dimiliki terbatas dan fondasi batu yang terdapat di lokasi pembangunan memadai. Studi ini dilakukan dengan mendesain kedua tipe pelimpah sehingga hasilnya dapat dibandingkan. Data-data primer dan sekunder diperoleh melalui observasi, perhitungan, dan dari instansi-instansi lain. Kemudian, data tersebut diolah dan dianalisis dengan kelengkapan studi pustaka, termasuk kaidah-kaidah desain yang berlaku secara nasional/internasional. Hasil studi menunjukkan bahwa pelimpah tipe chute spillway lebih efektif dan lebih layak dibangun daripada tipe drop inlet karena dimensinya optimal, lebih ekonomis, serta lebih mudah pelaksanaannya di lapangan.