Core-edge 2D fluid modeling of full tokamak discharge with varying magnetic equilibrium: from WEST start-up to ramp-down

In the present work we investigate for the first time the 2D fluid transport of the plasma in WEST during an entire discharge from the start-up to the ramp-down (shot #54487). The evolution of density profile, electron and ion temperatures together with the experimental magnetic equilibrium, total current and gas-puff rate is investigated. Comparisons with the interferometry diagnostic show a remarkable overall qualitative agreement during the discharge that can be quantitative at some locations in the plasma core. If at the onset of the X-points during the ramp-up the electron heat flux is dominant at the target, present results show that the ion heat flux becomes dominant during the stationary phase of the discharge. Using a simple model for erosion, present results assess the tungsten sputtering due to deuterium ions during the start-up and ramp-up phases of the discharge and confirms the need to consider full discharge simulation to accurately treat the W source of contamination. This work also demonstrates the interest of developing magnetic equilibrium free solver including efficient time integration to step toward predictive capabilities in the future for fusion operation.

SWAT Application for Gajahwong River Streamflow Simulation

Gadjahwong River flows along Daerah Istimewa Yogyakarta (DIY) that is located in southern Java Island. Gadjahwong River has an important role for water supply purpose especially for agriculture activities. On the other hand, DIY is seeing 1.18% population growth each year. The population surge influences land cover change that can seize continuous discharge of Gadjahwong River. Therefore, continuous discharge simulation needs to be conducted for assessing Gadjahwong River water availability. Soil and Water Assessment Tool (SWAT) was employed for modelling Gadjahwong River streamflow discharge. The simulation result discharge was compared with observed data acquired at AWLR Wonokromo by using NSE and R2 statistical parameter. Finally, the statistical parameter was applied to justify quality of simulation. Findings showed that daily time step yielded NSE value of 0.61, R2 value of 0.79, and PBIAS value of -2.41%. Overall, the simulation showed good result based the statistical parameters.

Partial Discharge Simulation of Air Gap Defects in Oil-Paper Insulation Paperboard of Converter Transformer under Different Ratios of AC–DC Combined Voltage

A converter transformer is important primary equipment in a DC transmission project. The voltage on the valve side winding is complex when the equipment is running, including DC, AC, and AC–DC combined voltage. The insulation structure of the valve side winding of a converter transformer is an oil-paper insulation structure, which may have a variety of defects in the manufacturing stage and daily use, resulting in partial discharge. Therefore, it is the key to studying the partial discharge characteristics and mechanism of oil-paper insulation under AC–DC combined voltage. In this paper, we build a two-dimensional air gap model of oil-paper-insulated pressboard considering the actual particles and actual reaction based on the fluid model. The characteristics and evolution mechanism of partial discharge (PD) in pressboard under different AC/DC combined voltages are studied by numerical simulation. The results show that when the DC component increases, the polarity effect of partial discharge is more obvious, while the potential and discharge intensity in the air gap decrease. Further analysis revealed that the DC component in the combined voltage accumulated a large number of surface charges on the surface of the air gap, and the space charge distribution was more uniform and dispersed, which generated an electric field with opposite polarity to the DC component in the air gap and, then, inhibited the development of local discharge in the paperboard. The results of the simulation are consistent with the previous experimental phenomena, and the mechanism analysis of the simulation results also verifies the previous analysis on the mechanism of experimental phenomena. This will lay a theoretical foundation for the further study of partial discharge phenomenon of oil-paper insulation structures in practical operation in the future.

Application of the Regression-Augmented Regionalization Approach for BTOP Model in Ungauged Basins

Ten years after the Predictions in Ungauged Basins (PUB) initiative was put forward, known as the post-PUB era (2013 onwards), reducing uncertainty in hydrological prediction in ungauged basins still receives considerable attention. This integration or optimization of the traditional regionalization approaches is an effective way to improve the river discharge simulation in the ungauged basins. In the Jialing River, southwest of China, the regression equations of hydrological model parameters and watershed characteristic factors were firstly established, based on the block-wise use of TOPMODEL (BTOP). This paper explored the application of twelve regionalization approaches that were combined with the spatial proximity, physical similarity, integration similarity, and regression-augmented approach in five ungauged target basins. The results showed that the spatial proximity approach performs best in the river discharge simulation of the studied basins, while the regression-augmented regionalization approach is satisfactory as well, indicating a good potential for the application in ungauged basins. However, for the regression-augmented approach, the number of watershed characteristic factors considered in the regression equation impacts the simulated effect, implying that the determination of optimal watershed characteristic factors set by the model parameter regression equation is a crux for the regression-augmented approach, and the regression strength may also be an influencing factor. These findings provide meaningful information to establish a parametric transfer equation, as well as references for the application in data-sparse regions for the BTOP model. Future research should address the classification of the donor basins under the spatial distance between the reference basin and the target basin, and build regression equations of model parameters adopted to regression-augmented regionalization in each classification group, to further explore this approach’s potential.

Developing Floating Constructed Wetland in Laboratory Scale as Domestic Waste Contaminant Reductor in Urban Waters

Low awareness of sanitation of urban citizens creates negative effects on the environment which varied. The triggering factors of the phenomenon are education and conservation technology. A conservation technology, eco-technology e.g. constructed wetlands, is proposed to solve the problem. Laboratory work is conducted to obtain comprehensive analysis about floating constructed wetland. The research paper aims to illustrate the efficiency performance of constructed wetlands, with domestic species, in the lab-scaled area from urban wastewater. The constructed wetland media is prepared horizontally. The analysis of its performance leads to a discussion of urban water quality. Samplings and laboratory tests are conducted to examine pH, phosphorus, nitrogen, suspended solids, conductivity, COD, and BOD. The benefit of Nasturtium officinale as FTW media reduce phosphate, nitrate, and BOD as 100% in 14 days. The discharge simulation during 14 days reduce TDS and TSS as 100%.

Error Characteristics and Scale Dependence of Current Satellite Precipitation Estimates Products in Hydrological Modeling

Satellite precipitation estimates (SPEs) are promising alternatives to gauge observations for hydrological applications (e.g., streamflow simulation), especially in remote areas with sparse observation networks. However, the existing SPEs products are still biased due to imperfections in retrieval algorithms, data sources and post-processing, which makes the effective use of SPEs a challenge, especially at different spatial and temporal scales. In this study, we used a distributed hydrological model to evaluate the simulated discharge from eight quasi-global SPEs at different spatial scales and explored their potential scale effects of SPEs on a cascade of basins ranging from approximately 100 to 130,000 km2. The results indicate that, regardless of the difference in the accuracy of various SPEs, there is indeed a scale effect in their application in discharge simulation. Specifically, when the catchment area is larger than 20,000 km2, the overall performance of discharge simulation emerges an ascending trend with the increase of catchment area due to the river routing and spatial averaging. Whereas below 20,000 km2, the discharge simulation capability of the SPEs is more randomized and relies heavily on local precipitation accuracy. Our study also highlights the need to evaluate SPEs or other precipitation products (e.g., merge product or reanalysis data) not only at the limited station scale, but also at a finer scale depending on the practical application requirements. Here we have verified that the existing SPEs are scale-dependent in hydrological simulation, and they are not enough to be directly used in very fine scale distributed hydrological simulations (e.g., flash flood). More advanced retrieval algorithms, data sources and bias correction methods are needed to further improve the overall quality of SPEs.

Application of the SWAT hydrological model in flow and solid discharge simulation as a management tool of the Indaia River Basin, Alto São Francisco, Minas Gerais

Measurement and evaluation of soil erosion and consequent sediment yield are fundamental in the planning and management of watersheds, as they allow the identification of critical areas susceptible to erosive processes. This study analyzed the sediment yield generated by water erosion in the Indaia River Basin, Alto São Francisco, Minas Gerais, by using the SWAT hydrological model. From a regional/local scale, the initial simulation of the variables (flow and solid discharge) was performed on a monthly scale from 1988 to 2017. Then, parameter-sensitivity analysis, calibration, and validation of the model were executed. In the monthly calibration (1988 to 2007), the performance of the simulations for flow was R2=0.92 and NSE=0.91 and for total solid discharge R2=0.51 and NSE=0.50. In the monthly validation (2008 to 2017) for flow, R2=0.85 and NSE=0.82 was obtained and for total solid discharge R2=0.19 and NSE=0.16. Despite the unsatisfactory result in the validation stage, the model was able to analyze the distribution of sediment production by sub-basins or even by the Hydrologic Response Unit (HRU). Therefore, a sediment-yield map was generated which qualitatively indicated a tendency for greater erosive processes in the central portion of the basin. The results will support public policies mitigating environmental degradation of the Indaia River Basin.

EVALUASI PERENCANAAN DRAINASE MENGGUNAKAN SIMULASI HEC RAS 4.0 ( Studi Kasus : Jalan Budiman – Tembilahan)

The rapid development of the city has resulted in the development of development in each city getting more massive with a relatively fast duration of development. This has very significant impacts on the livelihoods of the people. One of the impacts is flooding that occurs due to wrong land use and improper drainage makers. Drainage as a diversion system for excess water is needed to divert water that falls into the road body and tackle inundation that occurs when it rains. This is intended to reduce the risk of accidents due to slipping of tires due to water. The planning of the road surface drainage system in the case of the Budiman Kota Tembilahan road needs important attention in order to avoid flooding or accidents. In this study, an analysis of drainage planning was carried out with a simulation using hecras 4.0 software to simulate the planned drainage conditions on Jalan Budiman, Tembilahan city. After collecting data on the length of the drainage channel on Jalan Budiman, Tembilahan city and Catchment for the residential area on Jalan Budiman, Tembilahan city, as well as rainfall data for the last 10 years, the planned discharge and drainage for the drainage of Jalan Budiman, Tembilahan city are Qrencana = 0,141 m3/dt dan Qsaluran = 0,264 m3/dt dimana Qs > Qr with a rectangular cross section. Then the calculation simulation can be done using HEC-RAS 4.0 software. The results of the analysis of the drainage planning of Tembilahan city roads state that the planned drainage using hecras simulations based on manual calculations is able to accommodate discharge and no runoff. Keywords: Hec ras 4.0, discharge , simulation Abstrak Pesatnya perkembangan kota mengakibatkan perkembangan pembangunan pada tiap – tiap kota semakin masif dengan durasi perkembangan yang relatif cepat. Hal tersebut memiliki dampak – dampak yang sangat signifikan bagi hajat hidup warga. Salah satu dampaknya ialah banjir yg terjadi diakibatkan tata guna lahan yang salah dan pembuat drainase yang tidak tepat. Drainase sebagai sistem pengalih kelebihan air sangat diperlukan untuk mengalihkan air yang jatuh ke badan jalan dan menanggulangi genangan yang terjadi ketika hujan. Hal tersebut dimaksudkan untuk menggurangi resiko kecelakaan karena tergelincirnya ban akibat air. Perencanaan sistem drainase permukaan jalan dalam kasus jalan budiman kota tembilahan perlu mendapat perhatian yang penting guna terhindar dari genangan banjir atau kecelakaan. Pada penelitian ini dilakukan analisis perencanaan drainase dengan simulasi menggunakan software hecras 4.0 guna mensimulasilkan kondisi drainase yang direncanakan pada Jalan Budiman kota Tembilahan. Setelah mengumpulkan data panjang saluran drainase di jalan Budiman kota Tembilahan dan Catchment Area pemukiman di Jalan Budiman kota Tembilahan, serta data curah hujan 10 tahun terakhir diperoleh debit rencana dan debit saluran untuk drainase Jalan Budiman kota Tembilahan adalah Qrencana = 0,141 m3/dt dan Qsaluran = 0,264 m3/dt dimana Qs > Qr dengan penampang persegi empat. Kemudian dapat dilakukan simulasi perhitungan menggunakan software HEC-RAS 4.0.Hasil dari Analisis perencanaan drainase jalan budiman kota tembilahan menyatakan drainase yang direncanakan dengan menggunakan simulasi hecras yang berdasarkan hitungan manual mampu mengakomodasi debit dan tidak terjadi limpasan. Kata kunci: Hec Ras 4.0, Debit, simulasi

PREDIKSI DEBIT SUNGAI BENGAWAN SOLO MENGGUNAKAN NUMERICAL WEATHER MODEL GLOBAL FORECAST SYSTEM DAN INTEGRATED FLOOD ANALYSIS SYSTEM (Prediction of discharge in Bengawan Solo River using Numerical Weather Model Global Forecast System and Integrated Flood Analysis System)

Flood is one of the most common hydro-meteorological disasters. Bengawan Solo is one of the watersheds in Indonesia that also hit by this disaster. This study discusses the flood disaster in the Bengawan Solo area in early March 2019. The purpose of this study is to conduct a discharge simulation using numerical weather model Global Forecast System (GFS) data through Integrated Flood Analysis System (IFAS) so it is possible to predict discharge in the future. There are three types of numerical weather model GFS data that have been downscale using weather research and forecasting model which differentiated based on spin-up time. The numerical weather model product is then used as rainfall data input for IFAS simulation. Based on the analysis, the flood discharge simulation using an 84-hour spin-up time has a satisfactory performance in describing the change in discharge with respect to time. This happens because numerical weather models will be better at quantifying processes that occur on a meso scale with spatial scale of 10 to 1000 km. The result of this research shows that it is possible to predict river discharge up to 84 hours before the disaster so this is can support the mitigation process for hydrometeorological disasters.