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Monitoring models for base flow effect and daily variation of dam seepage elements considering time lag effect

Water Science and Engineering 2018年第4期11卷 344-354页

作者： Shao-wei Wang Ying-li Xu Chong-shi Gu Teng-fei Bao School of Environmental and Safety Engineering Changzhou University State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University

Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity *** analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.

关键词： Dam seepage monitoring model Time lag effect Support vector machine(SVM) Sensitivity analysis base flow Daily variation Piezometric tube water level

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Numerical Analysis of Cavity-based Control of base Pressure Variations at Supersonic Mach Numbers

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Fluid Dynamics & Materials Processing 2023年第6期19卷 1655-1677页

作者： Ridwan Sher Afghan Khan Jaffar Syed Mohamed Ali Mohd.Azan Mohammed Sapardi Abdul Aabid Mechanical and Aerospace Engineering Department Faculty of EngineeringInternational Islamic UniversityKuala Lumpur53100Malaysia Department of Engineering Management College of EngineeringPrince Sultan UniversityRiyadh11586Saudi Arabia

In the present study,the base pressure variations induced by the presence of a cavity,known to have a strong influence of the behaviour of supersonic projectiles,are investigated through numerical solution of the balance equations for mass,momentum,and *** area ratio of four is considered and numerical simulations are carried out at Mach M=1.2,1.4,1.6,and 1.8 assuming no cavity or cavity locations 0.5D,1D,1.5D,and *** inlet pressure of the nozzle is considered as a flow *** Taguchi method is also used,and the considered cases are then analyzed using a full factorial experimental *** results show that the cavity is effective in increasing the base pressure for the conditions *** other nozzle pressure ratios,cavities do not lead to passive control due the change in the reattachment *** distribution of wall pressure reveals that,in general,a cavity used to implement passive control of the base pressure does not adversely influence the flow pattern in the domain.

关键词： Mach number cavity Taguchi base flow base drag

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Sensitivity Assessment for Soil Hydraulic Conductivity in a Coupled Surface-Subsurface Water flow Model

Sensitivity Assessment for Soil Hydraulic Conductivity in a ...

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水资源管理与工程国际学术会议

作者： Qi ZHANG State Key Laboratory of Lake Science and Environment Nanjing Institute of Geography and Limnology.Chinese Academy of Sciences Nanjing.210008.China

＜正＞For coupled surface-subsurface water flow modeling,the soil layer is an important domain since it affects both the generation of surface runoff and water flux between surface and groundwater *** is a need to assess how the soil physical parameters affect the modeling results to help guide field measurements and model parameter *** paper investigates the sensitivity of the modeling results in response to the soil hydraulic conductivity by performing a surface-subsurface water flow simulation for a sub catchment of Lake *** indicate that soil lateral flow and groundwater recharge are the most sensitive flow components to the change of soil hydraulic *** increase in soil hydraulic conductivity results in an increase in these *** increase in groundwater recharge consequently causes the rise of groundwater table for the catchment,which induces more groundwater discharge to rivers as base *** is worthy to note that a change of soil hydraulic conductivity less than 30%does not cause a noticeable change in flow components. It is also interesting to notice that the model prediction accuracy of river discharge is not sensitive to the change of soil hydraulic conductivity,which implies that assessment of simulation accuracy and model validation using river discharge solely may not be sufficient for a surface-subsurface water flow simulation. Internal flow components are important and essential to use for a more reliable model validation.

关键词： Soil hydraulic conductivity sensitivity seeseement base flow groundwater recharge soil lateral flow coupled hydrological modeling WATLAC

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