Hasil untuk "Hydraulic engineering"

R. Baxter

M. Zupanc, Žiga Pandur, Tadej Stepišnik Perdih et al.

A sudden decrease in pressure triggers the formation of vapour and gas bubbles inside a liquid medium (also called cavitation). This leads to many (key) engineering problems: material loss, noise, and vibration of hydraulic machinery. On the other hand, cavitation is a potentially useful phenomenon: the extreme conditions are increasingly used for a wide variety of applications such as surface cleaning, enhanced chemistry, and wastewater treatment (bacteria eradication and virus inactivation). Despite this significant progress, a large gap persists between the understanding of the mechanisms that contribute to the effects of cavitation and its application. Although engineers are already commercializing devices that employ cavitation, we are still not able to answer the fundamental question: What precisely are the mechanisms how bubbles can clean, disinfect, kill bacteria and enhance chemical activity? The present paper is a thorough review of the recent (from 2005 onward) work done in the fields of cavitation-assisted microorganism's destruction and aims to serve as a foundation to build on in the next years.

Ya-Sin Yang, Hsin-Fu Yeh, Chia-Chi Huang et al.

Abstract Given the pressures on water resources caused by global climate change and human activities, the assessment and management of groundwater resources in mountainous region have become increasingly important. The central mountainous region of Taiwan, as one of the significant sources of groundwater recharge, plays a critical role in overall water resource management due to its groundwater storage capacity and recharge capability. Addressing the challenges of limited survey and observational data in mountainous groundwater assessments, this study uses the lumped parameter groundwater model AquiMod to analyze long-term groundwater level changes at 23 monitoring stations in mountainous areas of central Taiwan. This study is based on long-term groundwater level monitoring data (2010–2021) analyzing the relationship between groundwater levels and precipitation, and performs model calibration and prediction. The results indicate a strong correlation between groundwater levels in mountainous areas and precipitation. While the model predictions were satisfactory for most monitoring stations, obtaining Nash Sutcliffe efficiency scores of between 0.5 and 0.9 at 14 of the 23 monitoring stations. However, poorer performance at several stations reflects limitations arising from data gaps, complex local geology, and the inability of the lumped model to represent lateral recharge or anthropogenic influences. Model sensitivity analysis further highlights the critical role of unsaturated zone parameters, such as rooting depth, soil storage and upper-layer saturated hydraulic conductivity, in shaping groundwater responses. In summary, the lumped parameter groundwater model has proven practical for evaluating groundwater in Taiwan’s mountainous regions and can serve as a reference for the sustainable management of future water resources.

Maryam Rezaei

Evapotranspiration estimation is one of the most important water balance components and involves various complexities. In general, energy balance models are divided into two categories: single-source and two-source models. Choosing a model to estimate ET from among the existing energy balance models is challenging because each model has strengths and limitations. The goal of the present research is to introduce and compare several evapotranspiration estimation methods, including Surface Energy Balance Algorithm for Land (SEBAL) model, Mapping EvapoTranspiration at high Resolution with Internalized Calibration (METRIC) model, Surface Energy Balance System (SEBS) model, Simpled Surface Energy Balance Index (S-SEBI) model, Operational Simplified Surface Energy Balance (SSEBop) model— Two- Source (soil + canopy) (TSM) model and Two-Source Time Integrated (TSTIM) model. Some advantages of the single-source energy balance model S_SEBI include the following: It is possible to implement it using only images without the need for weather data. Therefore, if the number of meteorological stations in the area is low, this method can be utilized. No need for a land use map. One disadvantage of this model is that it can only be used in cases where atmospheric conditions across the entire image are constant. Due to the simplicity and lower complexity of the structure and assumptions of the SSEBop model, it has increased operational capability for calculating actual evapotranspiration over large areas. However, it is not recommended for regions with heterogeneous vegetation cover, mountainous areas, high albedo regions, or high levels of radiation, and in such areas, the TSEB algorithm is recommended. Due to some errors and uncertainties in these surface energy balance models, extensive studies are required to overcome these limitations.

Adrienne J Phillips, R. Gerlach, E. Lauchnor et al.

B. Barboza, Bin Chen, Chenfeng Li

Abstract Proppant transport is a critical physical process in hydraulic fracturing which has been extensively used for reservoir stimulation in petroleum engineering. Proppants injected together with fracturing fluid provide structural support to the stimulated fracture network and prevent them from closing after flowback. Hence, the final proppant distribution in fracture networks affects directly the effectiveness of hydraulic fracturing. Owing to the limitation and high cost of well logging, computational modelling has been increasingly used to study proppant transport, where different assumptions and numerical models have been employed often without rigorous validation or justification. This work presents a comprehensive review on proppant transport modelling, from relevant physics to numerical approaches, aiming to provide an unbiased global picture of the-state-of-the-art studies, inspire new insights, and promote the development of innovative and reliable computational models for proppant transport.

Yanlin Zhao, Qiang Liu, Hang Lin et al.

The hydromechanical coupling behavior of rocks is widely present in the fields of rock mechanics and engineering studies. Analyzing and summarizing the relevant literature, the current status of experimental and coupling theory research on hydromechanical coupling is systematically described, the commonly used numerical simulation methods and their applications are briefly introduced, and the hydromechanical coupling problems in mining engineering, water conservancy, and hydropower engineering, slope engineering, tunneling engineering, and other fields are analyzed. Regarding the current status of studies on the hydromechanical coupling behavior of rocks, the test research aspect needs to further enhance the test studies on the triaxial shear permeability of rock material, and adopt a combination of macroscopic, fine, and microscopic methods to study the hydraulic coupling problems of rock materials from different scales. To couple theory, the traditional concepts are broken through, and new coupling theories and mathematical models are used to explain and solve the relevant practical problems. Meanwhile, the application of interdisciplinary approaches to solving coupling problems in the future is emphasized. In terms of numerical simulation and engineering applications, new large data algorithms are developed to improve the efficiency of simulation calculations. In addition, consideration should be given to the numerical simulation of coupling effects, the coupled rheological effects, and the coupled dynamic properties of rock masses under high-ground stress and high water pressure.

Hongjun Joo, Wonyoung Choi, Chansoo Jeon

Abstract Floods are the most frequent types of natural disasters. From the perspective of disaster management, indicators associated with floods are important for accurate flood risk assessment. However, the application of all indicators related to flood risk assessment decreases the evaluation efficiency, because the definitions of the indicators may overlap. Moreover, the volume of data required for collection and evaluation is significantly large, making the evaluation practically impossible. Thus, a scientific and objective method to select indicators for flood risk assessment based on the entropy theory was developed herein. First, the existing 28 assessment indicators were analyzed and probability‐based data were constructed for each indicator considering 28 districts in a midwestern region of Korea. The information quantity for each indicator was then obtained using marginal entropy and mutual information generated in the entropy theory. Next, the total information quantity based on the numbers of combination of indicators was derived by considering the information quantity for each indicator and the overlapping mutual information between the indicators. The maximum amount of information (161.55) was obtained by combining 18 out of the 28 flood risk indicators. The selected 18 indicators reflected regional characteristics better than those used in the existing method, demonstrating that the flood risk of the target area could be adequately assessed.

Caleb Renner, Nathan Conroy, Evan Thaler et al.

Rainfall frequency and intensity are expected to increase in the Arctic, with potential detrimental impacts on permafrost, leading to enhanced thawing and carbon release to the atmosphere. However, there have been very few studies on the effect of discrete rain events on permafrost in the Arctic and sub-Arctic. Conducting controlled rainfall experiments within permafrost landscapes can provide an improved understanding of the effect of changing intensity, duration, and timing of rain events on permafrost tundra ecosystems. Here, we describe the design and implementation of the Next-Generation Ecosystem Experiment Arctic Rainfall Simulator (NARS), a variable intensity (4–82 mm/h) rainfall simulator that can be used to study the effects of rainfall on permafrost stability. The NARS design includes a 3D-printed 4 cm H-flume and uses an eTape resistivity sensor that was calibrated (R2 = 0.9–0.96) to measure discharge from the system. NARS is designed to be lightweight, simple to construct, and can be easily deployed in remote locations. As a field validation of updated rainfall simulator design and modernized controls, NARS was tested on the Seward Peninsula, AK. Because of its portability, versatility in deployment, dimensions, and rainfall intensity, NARS represents a methodological innovation for researching the impacts of rainfall on permafrost environments. HIGHLIGHTS Rainfall is expected to increase in the Arctic over the next century.; The effects of rainfall on permafrost stability are poorly understood.; We developed a variable intensity rainfall simulator for use in remote areas.; The new rainfall simulator is lightweight and modernizes simulator controls.; The simulator can be used to study rain effects on permafrost.;

Lilang Pi, Chunfang Yue, Jiachen Shi

Deformation is a critical indicator of structural integrity, and monitoring deformation is essential for ensuring the long-term safety of dams. However, characterizing the spatial correlations among dam deformation sequences and the similarity between displacements at various measurement points poses significant challenges when using single-point measurement models. Considering the limitations inherent in conventional models for processing spatiotemporal data, this paper introduces a novel model for predicting and imputing multi-point displacement monitoring data from earth-rock dams. The model integrates a convolutional neural network (CNN) with a bidirectional long short-term memory neural network (BiLSTM) while also incorporating an attention mechanism (AM). The CNN captures the spatial features of the displacement data, while the BiLSTM extracts temporal features. The AM assigns varying weights to input features, thereby enhancing the predictive accuracy of the model. The proposed model was experimentally validated, demonstrating its robust capabilities in data prediction and the imputation of missing data. The model provides a new strategy for forecasting dam deformation and addressing issues related to incomplete data.

S Kumar, S. Rani

Water waves, a common natural phenomenon, have been influential in various fields, such as energy development, offshore engineering, mechanical engineering, and hydraulic engineering. To describe the shallow water waves near an ocean coast or in a lake, we use the (1 + 1)-dimensions Boussinesq–Burgers system. By means of Lie symmetry analysis, symmetry groups and infinitesimal generators are obtained for the (1 + 1)-dimension Boussinesq–Burgers system. For the sake of finding the invariant solutions of the Boussinesq–Burgers system, the optimal one-dimensional subalgebra system is computed. Furthermore, using similarity reduction and the generalized Kudryashov method, we attain the abundant wave solutions of the Boussinesq–Burgers system presented in this research paper. Additionally, the exact solutions, which illustrate the effectiveness of the proposed method, also reveal the physical interpretation of the nonlinear models. To demonstrate the significance of interaction phenomena, dynamical behaviors of some attained solutions are depicted geometrically and theoretically through suitable parameter values. Consequently, kink, singular, periodic, solitary wave solutions, and their elastic nature have been shown to validate these solutions with physical phenomena. With the aid of the obtained results, the researchers could gain an understanding of the different modes of shallow water waves nearby an ocean beach. The computational work ascertained that the imposed methods are sturdy, precise, modest, and widely applicable.

Fei-Yan Liu, Yi Gao, Xin Yu et al.

Enrique Cabrera, Miguel Ortiz, Elena Gómez et al.

El presente trabajo analiza el comportamiento energético de los sistemas de transporte de agua a presión simples, en los que una tubería trasiega agua desde el punto origen hasta el final. El objetivo del análisis es evaluar la eficiencia energética del sistema y, a partir de ella, formular una propuesta de certificación energética. Para ello, se calculan tres valores representativos del indicador intensidad energética Ie, (kWh/m3): la intensidad energética ideal Iei; la Intensidad energética real Ier, cociente entre la energía realmente consumida (kWh) y el volumen trasegado (m3) en idéntico periodo de tiempo, y, por último, la Intensidad energética objetivo, Ieo, valor de la energía unitaria suponiendo un funcionamiento real óptimo. El resultado del cociente Ier/Ieo sintetiza el margen de mejora del sistema y, por tanto, es el utilizado para calificar su eficiencia energética. El trabajo concluye con un ejemplo real que reproduce el procedimiento establecido.

Xiazhong Zheng, Chenfei Duan, Yun Chen et al.

Study region: Major urban areas in Henan Province of central China. Study focus: data fusion technology is also a key and difficult point in the field of flood research. Remote sensing and text data have different modalities and scales, making fusion difficult. This study proposed a remote sensing and text bimodal data fusion model based on UFCLI, and we validated the spatiotemporal distribution of floods and the calculation results of disaster losses. The results show that through the coupling analysis of remote sensing and text bimodal data, rainstorm and flood events can be fully reproduced in space and time. The proposed UFCLI effectively improves the accuracy of remote sensing single-data inversion for urban flood disaster losses. The flood loss in Henan is 121.98 billion yuan, and the accuracy improvement result is R² increased by 0.08 and MAPE decreased by 0.88. New hydrological insights for the region: In the case of sudden urban storm flooding with complex spatial and temporal evolution, the traditional hydrological-hydraulic model has many pending parameters, which makes it difficult to accurately calculate large-scale disaster losses. By establishing a theoretical model of bimodal data fusion, we effectively use the complementary spatiotemporal information using remote sensing and text to solve the differences in spatiotemporal scales existing between remote sensing and text data. The timeliness and accuracy of urban flood damage estimation have further improved. Data Availability Statement: Not applicable.

Chen Zhu, Michael Meurer, Christoph Günther

Camera-based visual navigation has great potential for various applications, especially in satellite-signal-degenerated environments. However, the lack of integrity protection has constrained its utilization in safety-critical applications. Integrity characterizes the quality of the information that a navigation system delivers. Integrity frameworks have been developed over decades for satellite navigation, and continue to play an essential role in safety-critical applications like civil aviation. Nevertheless, there are several challenges to quantify the risks associated with visual navigation. Over the last few years, several approaches to tackle these challenges have been investigated. These developments are the first steps toward a reliable visual positioning framework with integrity monitoring capabilities. In this paper, we review the current status, particular challenges, and development trends in visual positioning integrity monitoring. In addition, we propose a preliminary framework so that the future developments on visual navigation integrity can benefit from a systematic approach.

Jesline Joy, Mehrdad Raisee, Michel J. Cervantes

The present paper demonstrates a proof-of-concept by introducing a variable guide vane system in the draft tube of a high-head Francis model turbine. The aim is to examine the hydraulic performance of the turbine while mitigating the pressure pulsations in the draft tube. The guide vanes can rotate about an axis up to ±45°. The pressure pulsations mitigation studies were performed at lower- and upper-part loads. The hydraulic performance was examined at all operating ranges within the turbine head. There were six guide vane configurations considered between ±45°. The findings demonstrate that the highest efficiency loss with a guide vane configuration that mitigates the pressure pulsations is marginal, with modest improvements at the best efficiency point. The pressure pulsations are 100% mitigated at the lower part load, and there is a maximum decrement in the pressure pulsations up to 80% at the upper part load. The study demonstrates that such a system can improve the operational flexibility of the hydro-turbine by mitigating the pressure pulsations and marginally affecting its hydraulic performance.

Qin Ju, Rongrong Zhang, Guoqing Wang et al.

The processes of soil freezing-thawing lead to soil water and heat movement in cold regions, which significantly influences the hydrological and energy cycles in the soil-plant-atmosphere system. This study presents a soil water content coupled with heat transfer model based on physical processes of water and heat movement in frozen soil. The model was calibrated and validated using the measured data of soil temperature and frost and thaw depth at 19 stations in and around the Three-River Source Region of China. The results show that the frozen soil model could capture the processes of soil freezing-thawing processes well at this region. The relationship between model parameters and climate and vegetation factors was analyzed using the observation data and remote sensing data obtained from MODIS, and results showed that the parameter c which represents the soil properties has a good correlation with longitude and vegetation coverage. A multi-regression model was established to estimate the model parameters in regions without observation data and its determination coefficient R2 was 0.82. The mean relative error between calibration and inversion parameters of 19 stations is 6.29%. Thus, the proposed method can be applied to cold regions without observation data to obtain the parameters and simulated the soil freezing-thawing processes.

Saeed Rad, Dai Junfeng, Xu Jingxuan et al.

We analyzed the characteristics of main karstic/non-karst reaches of the Lijiang River to uncover the causes behind different flood behaviors by providing a better understanding of the flood formation. Having 63 years of rainfall-runoff data and applying the HEC-HMS model, geo/hydrological features were investigated. The available reservoir capacity of karts (ARCK) was included through soil moisture accounting loss data to assess its impact. In particular, the expected instantaneous peak discharge rates/times were found largely imbalanced with generated unit hydrographs. Moreover, significant gaps among the floods’ features for different subbasins in terms of required peak modifications (2–4 times larger for mid-upstream, respectively) were mainly associated with the unique karst structure and initial condition due to various ARCK in rainy/dry seasons. Besides, notable dissimilarities between the wedge/prism storage volumes and the hydrograph’s wave traveling/receding time were observed owing to the geomorphological conditions. Although the contribution rates of drivers in karst flood formation cannot be quantitively modeled, based on our results the ARCK emerged to play a substantial role on the forecasted results, comparatively. Our results suggest that since ARCK varies, taking it into account (as initial abstraction) results in a more reliable estimation. This was underpinned by the results in which the unmodified simulations had a qualified rate of 52% accuracy on average and increased to 67.5% after the ARCK inclusion. This work adds to the body of evidence illustrating that in karst hydrology, ignoring the situational circumstances in modeling might lead to inaccuracies in flood forecasting for such dynamic watersheds. HIGHLIGHTS Hydrological models inaccurately forecast flood features in karst basins.; The seasonality of available karst reservoir capacity drives flood peaks.; Initial conditions must be considered in model calibration for karstic areas.;

F. Cotecchia, C. Vitone, F. Sollecito et al.

Abstract The paper presents the results of the analysis of the geo-chemo-mechanical data gathered through an innovative multidisciplinary investigation campaign in the Mar Piccolo basin, a heavily polluted marine bay aside the town of Taranto (Southern Italy). The basin is part of an area declared at high environmental risk by the Italian government. The cutting-edge approach to the environmental characterization of the site was promoted by the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto and involved experts from several research fields, who cooperated to gather a new insight into the origin, distribution, mobility and fate of the contaminants within the basin. The investigation campaign was designed to implement advanced research methodologies and testing strategies. Differently from traditional investigation campaigns, aimed solely at the assessment of the contamination state within sediments lying in the top layers, the new campaign provided an interpretation of the geo-chemo-mechanical properties and state of the sediments forming the deposit at the seafloor. The integrated, multidisciplinary and holistic approach, that considered geotechnical engineering, electrical and electronical engineering, geological, sedimentological, mineralogical, hydraulic engineering, hydrological, chemical, geochemical, biological fields, supported a comprehensive understanding of the influence of the contamination on the hydro-mechanical properties of the sediments, which need to be accounted for in the selection and design of the risk mitigation measures. The findings of the research represent the input ingredients of the conceptual model of the site, premise to model the evolutionary contamination scenarios within the basin, of guidance for the environmental risk management. The study testifies the importance of the cooperative approach among researchers of different fields to fulfil the interpretation of complex polluted eco-systems.

Bahareh Bahari, Woongki Hwang, Tae-Hyung Kim et al.

Abstract Soil liquefaction which is a disastrous phenomenon induced by the earthquake, is widely investigated in many researches in geotechnical engineering. In this study, a SPT-N based investigation is carried out to assess the susceptibility of liquefaction in Eco-Delta city, located in the southwestern part of Busan city in South Korea. Data from 229 sites are analyzed for the earthquake of 7.5 magnitude with a peak horizontal acceleration of 0.2 g to carry out the liquefaction potential index (LPI) through two deterministic methods which have different factors of safety (FS). The liquefaction probability is investigated by the deterministic and reliability methods and the liquefaction hazard maps are generated. To observe the effect of fines content and plasticity index on the liquefaction susceptibility, three different cases are considered. It is found that among the four approaches used, Overseas Coastal Area Development Institute of Japan (OCDI) method showed more sensitivity to changes of fines content and plasticity index. The Eco-Delta city is found to be highly vulnerable to liquefaction having 91% of sites with LPI values greater than 15.