http://scholars.ntou.edu.tw/handle/123456789/163 Mon, 10 Aug 2026 19:44:56 GMT 2026-08-10T19:44:56Z https://scholars.ntou.edu.tw:443/retrieve/72/河海工程學系.jpg http://scholars.ntou.edu.tw/handle/123456789/163 http://scholars.ntou.edu.tw/handle/123456789/26808 標題: Greenwater due to plunging breaking wave impingement on a deck structure. Part 2: Impact pressure and air fraction 作者: Hsieh, Meng-Chang; Chuang, Wei-Liang; Lin, Ting-Chieh 摘要: Greenwater generated by plunging wave breakers can impose impulsive and highly localized loads on deck structures, yet the influence of entrained air remains insufficiently quantified because pressure and air fraction are rarely measured at nearly co-located positions. Extending the work of Chuang et al. (2023, Ocean Engineering, 287, 115859), this study simultaneously measures impact pressure and local air fraction on a rigid horizontal deck using a 40-point grid of flush-mounted pressure transducers and fiber-optic reflectometers. Two plunging-wave conditions representing near-edge and more inboard impacts were each repeated 30 times. Incident-wave repeatability and bootstrap convergence analyses were used to assess the adequacy of local ensemble means. Results show a narrow primary pressure peak when the water-rich plunging tongue reaches the deck, followed in some cases by delayed reloading associated with deformation and collapse of entrapped air cavities. The maximum ensemble-averaged pressure reached 15.58 kPa at X50-Z60 under the inboard-impact condition. Air-fraction measurements indicate rapid wetting near the lower probes and intermittent aeration near the upper probes. Higher local air fraction was associated with lower normalized peak pressure under the tested conditions, although the weak correlations and the influence of impact velocity and morphology preclude an isolated causal interpretation. Thu, 01 Jan 2026 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/26808 2026-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26782 標題: Development of Integrated Geomorphological and Hydrological GIS Platform for Prospective Dam Site Analysis 作者: Lee, Kwan Tun; Hsu, Yu-Han; Hung, Meng-Chiu; Huang, Pin-Chun; Chien, Ta-Chun; Lin, Yi-Ting; Liao, Yu-Hsun; Chen, Nai-Kuang; Hsu, Ching-Wen; Li, Ciao-Ru; Yang, Cho-Min; Chen, Lo-Ya; Chen, Jia-Qian; Ho, Jui-Yi; Lin, He-Chung; Lin, You-Huei; Tsai, Xiaoang 摘要: Constructing new reservoirs to ensure a reliable water supply in downstream areas and to alleviate overflow flooding along rivers during floods is an urgent task for the authorities. In this study, we developed a GIS platform that integrates a series of watershed geomorphological and hydrological models to assess the suitability of prospective dam sites. The built-in modules include watershed geomorphological analysis, rainfall analysis, flow analysis, surplus water analysis, and reservoir analysis. Using the digital elevation model, users can obtain the reservoir H-A-V curve at a prospective dam site and the upstream watershed's geomorphological factors. A topography-based hydrological model was used to estimate available water at the dam site, and surplus water was obtained by subtracting existing water demands and/or environmental flow requirements from the available water series. Exceedance probability analysis was then conducted for the surplus water to evaluate the dam site's feasibility for new water resources development. The system also provides a reservoir's useful-life evaluation to determine the time required for sediment accumulation to render the reservoir unable to serve its intended purpose. Moreover, for flood control, the platform includes a built-in module for estimating design discharge for different return periods. The planned Pingxi Reservoir site in New Taipei County, Taiwan, is used as an example in this study. Detailed analytical procedures are presented to demonstrate the use of the proposed integrated GIS platform system to assess the adequacy of prospective dam sites for new water resources development. Thu, 01 Jan 2026 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/26782 2026-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26775 標題: Effects of meteorological reconstruction on hydrological and deep learning streamflow models in Lanyang Watershed, Taiwan 作者: Tran, Nhat Thanh; Su, Yuan-Fong 摘要: Study region: The Lanyang River watershed in northeastern Taiwan, a steep mountainous basin characterized by strong climatic gradients and frequent discontinuities in meteorological observations. Study focus: To evaluate how different meteorological reconstruction methods influence watershed scale streamflow simulation using SWAT+ and deep learning models, and to quantify how variable specific reconstruction errors propagate through hydrological forecasts across multiple testing intervals. New hydrological insights for the region: Maximum and minimum temperature variables can be reconstructed reliably across stations, whereas precipitation remains the variable with the highest level of uncertainty even when supported by the high-resolution background fields provided by the Taiwan Climate Change Projection Information and Adaptation Knowledge Platform. Reconstruction quality directly affects hydrological behavior, as different machine learning reconstruction approaches modify streamflow timing, seasonal coherence, and event scale variability in distinct ways. Deep learning models, especially Long Short-Term Memory, outperform SWAT+ in temporal efficiency and variability reproduction, typically improving coefficient of efficiency (CE) by about 10-35% compared with SWAT+ model, demonstrating the value of combining improved meteorological reconstruction with advanced forecasting approaches to enhance hydrological reliability in this data scarce mountainous basin. Thu, 01 Jan 2026 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/26775 2026-01-01T00:00:00Z http://scholars.ntou.edu.tw/handle/123456789/26771 標題: Scattering of water waves in the presence of multiple porous structures over trench-type bottom topography 作者: Sahoo, Gagan; Tsai, Chia-Cheng; Behera, Harekrushna; Hsu, Tai-Wen 摘要: The present study examines the effectiveness of multiple finite-width porous structures in mitigating wave impact on the shorelines featuring trench-type bottom seabed. Wave propagation through thick porous structures is represented using the Sollitt and Cross model, utilizing the principles of small-amplitude water wave theory. The boundary value problem is converted into a system of linear algebraic equations through the eigenfunction expansion method, which is then solved numerically. The findings indicate that increasing the number of porous structures and trenches enhances wave reflection while reducing wave transmission. Analysis of the reflection coefficient's variation with wavenumber for various numbers of trenches and porous structures shows that wave reflection exhibits harmonic peaks followed by subharmonic peaks, with the amplitude of these peaks increasing up to certain wavenumbers before diminishing for higher wavenumbers. The scattering coefficients exhibit oscillatory and periodic patterns in response to changes in the spacing between trenches, porous structures, and the distance from the last trench to the first porous structure. Additionally, oscillatory and periodic patterns are observed in scattering coefficients as a function of trench width. In contrast, as the width of the porous structures increases, the wave reflection exhibits an oscillatory increasing pattern before eventually stabilizing at larger widths. Meanwhile, the transmission coefficient decreases and ultimately becomes zero. Furthermore, higher frictional coefficients result in an increased wave reflection and decreased wave transmission. However, a lower free surface elevation in the lee-side region Rt compared to the region R1 occurs due to multiple porous structures and trenches. With three trenches and four porous structures, the transmission coefficient is reduced to less than 3% , leading to a negligible free surface elevation in Rt . Notably, as the number of porous structures increases, the free surface elevation on the lee-side continues to decrease, even when the quantity of rubble mounds remains constant. This study underscores the potential of multiple porous structures in combination with trench-type bottoms for effective coastal protection. Thu, 01 Jan 2026 00:00:00 GMT http://scholars.ntou.edu.tw/handle/123456789/26771 2026-01-01T00:00:00Z