Claim Missing Document
Check
Articles

Found 3 Documents
Search
Journal : Journal of the Civil Engineering Forum

Numerical Simulation for One-Dimensional (1D) Wave Propagation by Solving the Shallow Water Equations using the Preissmann Implicit Scheme Prilla Lidyana; Bobby Minola Ginting; Doddi Yudianto
Journal of the Civil Engineering Forum Vol. 8 No. 2 (May 2022)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (524.503 KB) | DOI: 10.22146/jcef.3872

Abstract

This research simulated one-dimensional wave propagation by solving the shallow water equations using the Preissman implicit numerical scheme due to its ability to maintain simplicity and stability at a larger time step value. This numerical model was fundamentally developed to satisfy the shallow water condition, where the water depth or horizontal-length scale is much smaller than the free-surface disturbance wavelength or vertical-length scale, and to comprehensively test the accuracy of the model. Consequently, three different types of waves were considered and these include (1) tidal, (2) roll, and (3) solitary. In the first case, the model was proven to be robust and accurate due to its relatively-small errors for both water-surface elevation and velocity indicating that the Preismann scheme is suitable for longwave simulations. In the second case, it was fairly accurate in capturing the periodic permanent roll waves despite showing a higher water-surface elevation than the one observed and this discrepancy is due to the neglect of the turbulent Reynold stress in the model. Meanwhile, the last case showed remarkable discrepancies in the water-surface elevation because the dispersion effect is quite significant during the wave propagation. This indicates that the Preismann scheme underestimated the wave crest along with time when the dispersion term was neglected. All simulations were performed using the tridiagonal matrix algorithm, thereby eliminating the need for iterations for the solution of the Preismann scheme. The findings of this study are beneficial to the next generation of the Preissmann-scheme models which can be designed to include turbulence and dispersion terms.
Establishing a Simple-yet-effective Approach of Early Warning System for Storm-Induced Earth-Filled Dam-Break Cases in Data-sparse Region Doddi Yudianto; Farrell Wiguna; Bobby Minola Ginting; Albert Wicaksono; Xie Yuebo
Journal of the Civil Engineering Forum Vol. 9 No. 2 (May 2023)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jcef.6126

Abstract

Historically, the occurrence of dam-break cases has been proven to cause significant loss of life and economical damage. Apart from the catastrophic nature of dam-breaks, the absence of a robust disaster prevention system exacerbates the disasters that occur. This study proposes an Early Warning System (EWS) to mitigate the impact of dam-break disasters. However, predicting the occurrence of such disasters is challenging, specifically in areas like Indonesia, where comprehensive data recording is lacking. While it may be difficult to predict the occurrence of a sunny day break, the storm-induced break is more predictable. Therefore, this study proposes a simple yet effective macro-based EWS for Earth-Filled Dam-Break Cases using a macro approach based on the Evacuation Clearance Time (ECT). By comparing the ECT value with the arrival time of the floods from the affected areas, additional evacuation time can be obtained, which will be used to determine the EWS. The proposed EWS for Cengklik Dam is given in three levels of warning indicated by the reservoir water level at +141.36 m, +141.40 m, and +141.45 m. With the proposed EWS, the results show that 100% of people are expected to reach the evacuation point safely. The case study shows that the proposed EWS can significantly reduce the risk impact of the dam-break events.
Investigating the Capability of HEC-RAS Model for Tsunami Simulation Rifa Amaliah; Bobby Minola Ginting
Journal of the Civil Engineering Forum Vol. 9 No. 2 (May 2023)
Publisher : Department of Civil and Environmental Engineering, Faculty of Engineering, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jcef.6140

Abstract

This study highlights the simulation of tsunami cases using HEC-RAS 6.1. The primary aim is to evaluate the capability of the software in performing tsunami simulation due to its standalone computational framework (pre-processing, execution, and post-processing stages), making the modeling process interactive. The model accuracy was tested against some benchmark cases of wave propagation, including analytical solutions, laboratory experiments, and field measurements. The results showed HEC-RAS was capable of modeling tsunami propagation. The maximum elevation and velocity magnitude were accurately computed for the analytical cases. Furthermore, sufficiently accurate results were obtained for the laboratory case, where the maximum elevation was properly computed. For the field cases, the wave arrival time and the fluctuations of water surface and velocity were appropriately calculated. The Root Mean Square Error values between the numerical results and the analytical/observed data were relatively low below 30%, with the Pearson Product Moment Correlation values ranging from 52–99%. In addition to its eminence, a drawback was found regarding the graphical user interface (GUI) of HEC-RAS for the input of boundary conditions. These findings will be beneficial for the coastal engineering community and the continuous development of HEC-RAS.