scholarly journals Too many streams and not enough time or money? New analytical depletion functions for rapid and accurate streamflow depletion estimates

2020 ◽  
Author(s):  
Qiang Li ◽  
Tom Gleeson ◽  
Samuel C Zipper ◽  
Ben Kerr
Keyword(s):  
Numerical Models ◽  
Water Infiltration ◽  
Analytical Models ◽  
Groundwater Pumping ◽  
New Approach ◽  
Preliminary Screening ◽  
Support Tools ◽  
Simplifying Assumptions ◽  
Potential Groundwater ◽  
Streamflow Depletion

Groundwater pumping can cause streamflow depletion by reducing groundwater discharge to streams and/or inducing surface water infiltration. Analytical and numerical models are two standard methods to predict streamflow depletion. Numerical models require extensive data and efforts to develop robust estimates, while analytical models are easy to implement with low data and experience requirements but are limited by numerous simplifying assumptions. We have pioneered a new approach that balances the shortcomings of analytical and numerical models: analytical depletion functions, which include more empirical functions expanding the applicability of analytical models for real-world settings with complex hydrogeologic landscapes and stream networks. Specifically, analytical depletion functions combine analytical models with stream proximity criteria used to determine which stream segments are most likely to be affected by a pumping well and a depletion apportionment equation which is a geometric method to distribute depletion among the affected stream segments. The accuracy of analytical depletion functions has been tested by comparing against a variety of numerical models from simplified, archetypal models to sophisticated, calibrated models in both steady-state to transient conditions. Estimates of streamflow depletion from analytical depletion function generally agree with estimates from numerical models, suggesting analytical depletion functions are an accurate tool for the streamflow depletion assessment over diverse hydrogeological landscapes and scales. Analytical depletion functions are rapidly and easily implemented and have low data requirements like analytical models but have significant advantages of better agreement with numerical models and better representation of complex stream geometries. Relative to numerical models, analytical depletion functions have limited ability to explore non-pumping related impacts and incorporate subsurface heterogeneity. Analytical depletion functions can be used as a stand-alone tool or part of decision-support tools as preliminary screening of potential groundwater pumping impacts when issuing new and existing water licenses while ensuring streamflow meets environmental flow needs.

scholarly journals Quantifying Streamflow Depletion from Groundwater Pumping: A Practical Review of Past and Emerging Approaches for Water Management

2022 ◽  
Author(s):  
Samuel Zipper ◽  
William Farmer ◽  
Andrea Brookfield ◽  
Hoori Ajami ◽  
Howard Reeves ◽  
...  
Keyword(s):  
Numerical Models ◽  
Analytical Models ◽  
Future Research ◽  
Groundwater Pumping ◽  
Local Conditions ◽  
Conjunctive Management ◽  
High Data ◽  
Surface Water Resources ◽  
Inference Techniques ◽  
Streamflow Depletion

Groundwater pumping can cause reductions in streamflow (‘streamflow depletion’) that must be quantified for conjunctive management of groundwater and surface water resources. However, streamflow depletion cannot be measured directly and is challenging to estimate because pumping impacts are masked by streamflow variability due to other factors. Here, we conduct a management-focused review of analytical, numerical, and statistical models for estimating streamflow depletion and highlight promising emerging approaches. Analytical models are easy to implement, but include many assumptions about the stream and aquifer. Numerical models are widely used for streamflow depletion assessment and can represent many processes affecting streamflow, but have high data, expertise, and computational needs. Statistical approaches are a historically underutilized tool due to difficulty in attributing causality, but emerging causal inference techniques merit future research and development. We propose that streamflow depletion-related management questions can be divided into three broad categories (attribution, impacts, and mitigation) that influence which methodology is most appropriate. We then develop decision criteria for method selection based on suitability for local conditions and the management goal, actionability with current or obtainable data and resources, transparency with respect to process and uncertainties, and reproducibility.

THEORETICAL CARDIOLOGY: FROM MATHEMATICAL TO QUALITATIVE MODELS

1996 ◽  
Vol 04 (01) ◽  
pp. 131-150 ◽  
Author(s):  
P. SIREGAR
Keyword(s):  
Numerical Models ◽  
Analytical Models ◽  
Computational Framework ◽  
Cardiac Electrical Activity ◽  
Levels Of Detail ◽  
Multi Stage ◽  
Starting Point ◽  
Simplifying Assumptions ◽  
Qualitative Models ◽  
Predictive Role

A central concern in simulation studies is the adequation, or inadequation, of a designed model with respect to its intended goal. Models of cardiac electrical activity may differ in complexity, level of description and representation. Depending on the events to be be simulated, analytical, cellular automatas and qualitative models can be used. Their advantages and shortcomings can be put forth by comparing the space and time complexities, and if factors clinically relevant for studying arrhythmias and ischemias are taken into account in the respective models. In this paper, the factors under scrutiny are those characterizing impulse formation and conduction. If and how they are represented and computed constitutes a means of comparison between the models. The simplifying assumptions built into each can thus be put forth. Through illustrative examples, we then show that qualitative models can assume the explanatory and a predictive role usually devolved to numerical models. Such models can be used as a primer to quantification in a multi-stage process. A possibly useful development would be to integrate the analytical, cellular and qualitative models within a single computational framework. Central to this task is qualification. All piece of knowledge that is implicit in the mathematical or procedural representations has to be made explicit. Semantic links can thereafter be established between the models. This knowledge could be the starting point of a system emulating the reasoning of a theoretician working at different levels of detail. Its role would be to help researchers select, instantiate and interpret results of their most detailed cellular automata and/or analytical models.

scholarly journals Numerical Investigation of Elastomer Seal Performance

2021 ◽  
Author(s):  
Sayyad Zahid Qamar ◽  
Maaz Akhtar ◽  
Tasneem Pervez
Keyword(s):  
Numerical Models ◽  
Analytical Models ◽  
Oil Well ◽  
Actual Application ◽  
Open Hole ◽  
Simplifying Assumptions ◽  
Numerical Finite Element ◽  
Elastomeric Seals ◽  
Performance Analysis And Design ◽  
Elastomer Seal

Analytical models for swelling of rubberlike materials are difficult to formulate, and restricted in actual application due to their need for simplifying assumptions. Tests conducted on laboratory size samples of swelling elastomers cannot reproduce actual oil well conditions, and cannot cover all possible variations of testing parameters. However, these laboratory tests do provide useful information about material response of swellable elastomers in various conditions, serving as a basis for analytical and numerical modeling. Properly developed and robust numerical models can be used to predict near-actual performance of elastomeric seals. The current chapter describes the use of numerical (finite element) simulation to investigate swelling elastomer seal behavior in downhole petroleum applications. Variations in sealing (contact) pressure are studied for seal length, seal thickness, compression ratio, water salinity, swelling time, and type of well completion (open-hole or cased-hole). Month-long swelling experiments on samples of two actual elastomers (Chapters 3 and 7) provide input to the numerical model in terms of real material and deformation data. On the basis of these results, petroleum engineers can make informed decisions about the selection of elastomer material and seal geometry appropriate for the well type and conditions encountered. Application developers and researchers can also find this investigation useful in performance analysis and design of swelling elastomer seals.

scholarly journals Gaining a better understanding of the extrusion process in fused filament fabrication 3D printing: a review

2021 ◽  
Author(s):  
Bahaa Shaqour ◽  
Mohammad Abuabiah ◽  
Salameh Abdel-Fattah ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
...  
Keyword(s):  
3D Printing ◽  
Numerical Models ◽  
Extrusion Process ◽  
Analytical Models ◽  
Limiting Factor ◽  
Fused Filament Fabrication ◽  
Promising Tool ◽  
Relevant Work ◽  
3D Printing Technique ◽  
Required Quality

AbstractAdditive manufacturing is a promising tool that has proved its value in various applications. Among its technologies, the fused filament fabrication 3D printing technique stands out with its potential to serve a wide variety of applications, ranging from simple educational purposes to industrial and medical applications. However, as many materials and composites can be utilized for this technique, the processability of these materials can be a limiting factor for producing products with the required quality and properties. Over the past few years, many researchers have attempted to better understand the melt extrusion process during 3D printing. Moreover, other research groups have focused on optimizing the process by adjusting the process parameters. These attempts were conducted using different methods, including proposing analytical models, establishing numerical models, or experimental techniques. This review highlights the most relevant work from recent years on fused filament fabrication 3D printing and discusses the future perspectives of this 3D printing technology.

A New Approach for Determining Joint Stiffness of Bolted Joints

2014 ◽  
Vol 670-671 ◽  
pp. 1041-1044 ◽  
Author(s):  
Xi Wang Wang ◽  
Xiao Yang Li ◽  
Lin Lin Zhang ◽  
Xiao Guang Wang
Keyword(s):  
Accurate Determination ◽  
Joint Stiffness ◽  
Fatigue Loading ◽  
Bolted Joints ◽  
Analytical Models ◽  
Bolted Connection ◽  
New Approach ◽  
Axisymmetric Model ◽  
Force Equilibrium

Joint member stiffness in a bolted connection directly influence the safety of a design in regard to both static and fatigue loading as well as in the prevention of separation in the connection. Thus, the accurate determination of the stiffness is of extreme importance to predict the behavior of bolted assemblies. In this paper, An analytical 3D axisymmetric model of bolted joints is proposed to obtain the joint stiffness of Bolted Joints. Considering many different analytical models have been proposed to calculate the joint stiffness, the expression based force equilibrium can be a easy way to choose the best expression for the joint stiffness as a judgment criteria.

Impacts of Coal Mining on Groundwater Environment in Northwestern Coal Mine Area

2013 ◽  
Vol 448-453 ◽  
pp. 823-829
Author(s):  
Hao Wang
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Water Cycle ◽  
Numerical Models ◽  
Pumping Test ◽  
Field Investigation ◽  
Groundwater Pumping ◽  
Mine Area ◽  
Groundwater Environment ◽  
Groundwater Flow Field

By conducting field investigation and tests, such as groundwater pumping test and rock mechanics test, and building numerical models to simulate damage of coal mining to aquifers, it was proved that coal mining in some coal mine area caused impacts to groundwater environment, including impact on water cycle, the structure of aquifers, and groundwater flow field, as a result of which some water supply sources in coal mine area become unavailable. In addition, a couple of solutions are presented to mitigate the impacts.

Modelling of interactions between dykes, inclined sheets and faults at Santorini volcano

2021 ◽  
Author(s):  
Kyriaki Drymoni ◽  
John Browning ◽  
Agust Gudmundsson
Keyword(s):  
Tensile Strength ◽  
Fault Zone ◽  
Numerical Models ◽  
Damage Zone ◽  
Sheet Thickness ◽  
Analytical Models ◽  
Energy Conditions ◽  
Dyke Swarm ◽  
Normal Faults ◽  
Santorini Volcano

<p>Dykes and inclined sheets are known occasionally to exploit faults as parts of their paths, but the conditions that allow this to happen are still not fully understood. Here we report field observations from a well-exposed dyke swarm of the Santorini volcano, Greece, that show dykes and inclined sheets deflected into faults and the results of analytical and numerical models to explain the conditions for deflection. The deflected dykes and sheets belong to a local swarm of 91 dyke/sheet segments that was emplaced in a highly heterogeneous and anisotropic host rock and partially cut by some regional faults and a series of historic caldera collapses, the caldera walls providing, excellent exposures of the structures. The numerical models focus on a normal-fault dipping 65° with a damage zone composed of parallel layers or zones of progressively more compliant rocks with increasing distance from the fault rupture plane. We model sheet-intrusions dipping from 0˚ to 90˚ and with overpressures of alternatively 1 MPa and 5 MPa, approaching the fault. We further tested the effects of changing (1) the sheet thickness, (2) the fault-zone thickness, (3) the fault-zone dip-dimension (height), and (4) the loading by, alternatively, regional extension and compression. We find that the stiffness of the fault core, where a compliant core characterises recently active fault zones, has pronounced effects on the orientation and magnitudes of the local stresses and, thereby, on the likelihood of dyke/sheet deflection into the fault zone. Similarly, the analytical models, focusing on the fault-zone tensile strength and energy conditions for dyke/sheet deflection, indicate that dykes/sheets are most likely to be deflected into and use steeply dipping recently active (zero tensile-strength) normal faults as parts of their paths.</p>

A New Approach for Fatigue Damage Modeling of Subsurface-Initiated Spalling in Large Rolling Contacts

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Aditya A. Walvekar ◽  
Neil Paulson ◽  
Farshid Sadeghi ◽  
Nick Weinzapfel ◽  
Martin Correns ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Damage Mechanics ◽  
Numerical Models ◽  
Rolling Contact ◽  
Fe Model ◽  
Triangle Mesh ◽  
Computationally Efficient ◽  
New Approach ◽  
Rolling Contacts ◽  
Delaunay Triangle

Large bearings employed in wind turbine applications have half-contact widths that are usually greater than 1 mm. Previous numerical models developed to investigate rolling contact fatigue (RCF) require significant computational effort to study large rolling contacts. This work presents a new computationally efficient approach to investigate RCF life scatter and spall formation in large bearings. The modeling approach incorporates damage mechanics constitutive relations in the finite element (FE) model to capture fatigue damage. It utilizes Voronoi tessellation to account for variability occurring due to the randomness in the material microstructure. However, to make the model computationally efficient, a Delaunay triangle mesh was used in the FE model to compute stresses during a rolling contact pass. The stresses were then mapped onto the Voronoi domain to evaluate the fatigue damage that leads to the formation of surface spall. The Delaunay triangle mesh was dynamically refined around the damaged elements to capture the stress concentration accurately. The new approach was validated against previous numerical model for small rolling contacts. The scatter in the RCF lives and the progression of fatigue spalling for large bearings obtained from the model show good agreement with experimental results available in the open literature. The ratio of L10 lives for different sized bearings computed from the model correlates well with the formula derived from the basic life rating for radial roller bearing as per ISO 281. The model was then extended to study the effect of initial internal voids on RCF life. It was found that for the same initial void density, the L10 life decreases with the increase in the bearing size.

scholarly journals Modelling the high temperature oxidation of titanium alloys: review of analytical models and development of a new numerical tool PyTiOx

2020 ◽  
Vol 321 ◽  
pp. 06012
Author(s):  
C. Ciszak ◽  
D. Monceau ◽  
C. Desgranges
Keyword(s):  
Numerical Models ◽  
Ecological Impact ◽  
Operating Costs ◽  
Analytical Models ◽  
Temperature Oxidation ◽  
Ti Alloys ◽  
State Diffusion ◽  
First Results ◽  
Aeronautical Industry ◽  
Numerical Tool

In order to limit the ecological impact of air traffic and its operating costs, the aeronautical industry is looking for improving engines efficiencies and substitutes to high density Ni-based superalloys. Thus, a wider use of Ti-alloys operating at higher temperatures is one of the developed solutions. Being able to predict as accurately as possible the oxidation behavior of Ti-based components at high temperatures appears therefore crucial to improve their sizing and durability. Analytical models based on the solid-state diffusion laws can be found in the litterature. They are fairly accurate in most cases, but they reveal some intrinsic limitations in specific cases such as temperature transients or thin components. Numerical models were later developed to break down these limitations. First results from a new numerical tool called “PyTiOx” (still under development are presented here. They confirm the intrinsic limitations of analytical models. In the case of thin samples, the numerical model predicts an increase of scaling kinetic when metal becomes O-saturated, whereas analytical models do not.

scholarly journals Rapid and accurate estimates of streamflow depletion caused by groundwater pumping using analytical depletion functions

2018 ◽  
Author(s):  
Samuel Zipper ◽  
Tom Gleeson ◽  
Ben Kerr ◽  
Jeanette Howard ◽  
Melissa Rohde ◽  
...  
Keyword(s):  
Groundwater Pumping ◽  
Streamflow Depletion
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