scholarly journals Validation of a full-plasma integrated modeling approach on ASDEX Upgrade

2021 ◽  
Vol 61 (12) ◽  
pp. 126048
Author(s):  
T. Luda ◽  
C. Angioni ◽  
M.G. Dunne ◽  
E. Fable ◽  
A. Kallenbach ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Experimental Information ◽  
Integrated Model ◽  
Experimental Measurements ◽  
Baseline Scenario ◽  
Statistical Regression ◽  
Plasma Confinement ◽  
Modeling Framework ◽  
Energy Confinement Time ◽  
Engineering Parameters

Abstract In this work we present the extensive validation of a refined version of the integrated model based on engineering parameters (IMEP) introduced in reference (Luda et al 2020 Nucl. Fusion 60 036023). The modeling workflow is now fully automated, computationally faster thanks to the reduced radial resolution of the TGLF calculation, and it includes the modeling of the toroidal rotation, which was still taken from experimental measurements in our previous work. The updated model maintains the same accuracy as its previous version when tested on the cases presented in the initial publication. The confined plasma, from the magnetic axis to the separatrix, is simulated without using any experimental information from profiles measurements, and the inputs of IMEP are the same engineering parameters used when programming a plasma discharge. The model validation database consists of 50 ASDEX Upgrade (AUG) stationary (over a few energy confinement time) H-mode phases, which largely cover the entire AUG operational domain. The prediction of IMEP is compared with experimental measurements and with scaling laws, such as the IPB98(y,2), the ITPA20-IL, and AUG specific regressions. This modeling framework has proven to be very accurate over the entire set of 50 cases, with a significantly lower mean relative error with respect to each of the scaling laws considered, accurately reproducing the change in pedestal and core confinement caused by a change in plasma current, heating power, fueling rate, triangularity, magnetic field, NBI voltage (i.e. the effect of a change in the core particle source), and heating mix (e.g. correctly predicting the effect on confinement caused by a change in T e/T i). Plasma confinement is correctly described by IMEP also for two particular operating regimes, such as the ITER baseline scenario, and the QCE regime (quasi continuous exhaust, also referred as type-II and small ELMs). This work clearly demonstrates the power of this approach in pulling out physics mechanisms to interpret subtle interdependencies and that a 1D integrated model can reproduce experimental results over very large parameter variations with a higher accuracy than any statistical regression. This approach has therefore the potential to improve the prediction of the fusion performance in future tokamak reactors.

scholarly journals A new modeling framework for sea-ice mechanics based on elasto-brittle rheology

2011 ◽  
Vol 52 (57) ◽  
pp. 123-132 ◽  
Author(s):  
Lucas Girard ◽  
Sylvain Bouillon ◽  
Jérôme Weiss ◽  
David Amitrano ◽  
Thierry Fichefet ◽  
...  
Keyword(s):  
Sea Ice ◽  
Scaling Laws ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Good Representation ◽  
Strain Rates ◽  
Modeling Framework ◽  
Scaling Properties ◽  
Arctic Sea ◽  
Evaluation Metric

AbstractWe present a new modeling framework for sea-ice mechanics based on elasto-brittle (EB) behavior. the EB framework considers sea ice as a continuous elastic plate encountering progressive damage, simulating the opening of cracks and leads. As a result of long-range elastic interactions, the stress relaxation following a damage event can induce an avalanche of damage. Damage propagates in narrow linear features, resulting in a very heterogeneous strain field. Idealized simulations of the Arctic sea-ice cover are analyzed in terms of ice strain rates and contrasted to observations and simulations performed with the classical viscous–plastic (VP) rheology. the statistical and scaling properties of ice strain rates are used as the evaluation metric. We show that EB simulations give a good representation of the shear faulting mechanism that accommodates most sea-ice deformation. the distributions of strain rates and the scaling laws of ice deformation are well captured by the EB framework, which is not the case for VP simulations. These results suggest that the properties of ice deformation emerge from elasto-brittle ice-mechanical behavior and motivate the implementation of the EB framework in a global sea-ice model.

A Conceptual Design and Modeling Framework for Integrated Additive Manufacturing

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Hossein Mokhtarian ◽  
Eric Coatanéa ◽  
Henri Paris ◽  
Mouhamadou Mansour Mbow ◽  
Franck Pourroy ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Process Model ◽  
Conceptual Modeling ◽  
Three Dimensional ◽  
Integrated Model ◽  
Performance Model ◽  
Process Equipment ◽  
3D Printer ◽  
Fused Filament Fabrication ◽  
Modeling Framework

Modeling and simulation for additive manufacturing (AM) is commonly used in industry. Nevertheless, a central issue remaining is the integration of different models focusing on different objectives and targeting different levels of details. The objective of this work is to increase the prediction capability of characteristics and performances of additively manufactured parts and to co-design parts and processes. The paper contributes to this field of research by integrating part's performance model and additive technology process model into a single early integrated model. The paper uses the dimensional analysis conceptual modeling (DACM) framework in an AM perspective to generate causal graphs integrating the AM equipment and the part to be printed. DACM offers the possibility of integrating existing knowledge in the model. The framework supported by a computer tool produces a set of governing equations representing the relationships among the influencing variables of the integrated model. The systematic identification of the weaknesses and contradictions in the system and qualitative simulation of the system are some of the potential uses of the model. Ultimately, it is a way to create better designs of machines and parts, to control and qualify the manufacturing process, and to control three-dimensional (3D) printing processes. The DACM framework is tested on two cases of a 3D printer using the fused filament fabrication (FFF) powder bed fusion. The analysis, applied to the global system formed of the 3D printer and the part, illustrates the existence of contradictions. The analysis supports the early redesign of both parts and AM process (equipment) and later optimization of the control parameters.

An Integrated, Validated, and Applied Activity-Based Dynamic Traffic Assignment Model for the Baltimore-Washington Region

2018 ◽  
Vol 2672 (51) ◽  
pp. 45-55 ◽  
Author(s):  
Lei Zhang ◽  
Di Yang ◽  
Sepehr Ghader ◽  
Carlos Carrion ◽  
Chenfeng Xiong ◽  
...  
Keyword(s):  
Daily Activity ◽  
Travel Demand ◽  
Traffic Assignment ◽  
Dynamic Traffic Assignment ◽  
Integrated Model ◽  
Time Of Day ◽  
Practical Implementation ◽  
Baseline Scenario ◽  
Demand Model ◽  
Dynamic Traffic

The paper discusses the integration process and initial applications of a new model for the Baltimore-Washington region that integrates an activity-based travel demand model (ABM) with a dynamic traffic assignment (DTA) model. Specifically, the integrated model includes InSITE, an ABM developed for the Baltimore Metropolitan Council, and DTALite, a mesoscopic DTA model. The integrated model simulates the complete daily activity choices of individuals residing in the model region, including long-term choices, such as workplace location; daily activity patterns, including joint household activities and school escorting; activity location choices; time-of-day choices; mode choices; and route choices. The paper describes the model development and integration approach, including modeling challenges, such as the need to maintain consistency between the ABM and DTA models in terms of temporal and spatial resolution, and practical implementation issues, such as managing model run time and ensuring sufficient convergence of the model. The integrated model results have been validated against observed daily traffic volumes and vehicle-miles traveled (VMT) for various functional classes. A land-use change scenario that analyzes the redevelopment of the Port Covington area in Baltimore is applied and compared with the baseline scenario. The validation and application results suggest that the integrated model outperforms a static assignment-based ABM and could capture behavioral changes at much finer time resolutions.

Scaling laws of the energy confinement time in Stellarators without renormalization factors

2021 ◽  
Author(s):  
Andrea Murari ◽  
Emmanuele Peluso ◽  
Jesus Vega ◽  
José Manuel García Regaña ◽  
Jose Luis Velasco ◽  
...  
Keyword(s):  
Scaling Laws ◽  
Confinement Time ◽  
Energy Confinement ◽  
Energy Confinement Time

Robust scaling laws for energy confinement time, including radiated fraction, in Tokamaks

2017 ◽  
Vol 57 (12) ◽  
pp. 126017 ◽  
Author(s):  
A. Murari ◽  
E. Peluso ◽  
P. Gaudio ◽  
M. Gelfusa
Keyword(s):  
Scaling Laws ◽  
Confinement Time ◽  
Energy Confinement ◽  
Energy Confinement Time

scholarly journals Modeling Framework for Integrated, Model-based Development of Product-Service Systems

Procedia CIRP ◽  
2018 ◽  
Vol 73 ◽  
pp. 9-14 ◽  
Author(s):  
Hristo Apostolov ◽  
Matthias Fischer ◽  
Daniel Olivotti ◽  
Sonja Dreyer ◽  
Michael H. Breitner ◽  
...  
Keyword(s):  
Integrated Model ◽  
Service Systems ◽  
Modeling Framework ◽  
Model Based ◽  
Product Service ◽  
Product Service Systems

scholarly journals Influence of Evacuation Policy on Clearance Time under Large-Scale Chemical Accident: An Agent-Based Modeling

2020 ◽  
Vol 17 (24) ◽  
pp. 9442
Author(s):  
Minjun Kim ◽  
Gi-Hyoug Cho
Keyword(s):  
Large Scale ◽  
Dispersion Model ◽  
Baseline Scenario ◽  
Clearance Time ◽  
Residential Areas ◽  
Modeling Framework ◽  
Public Intervention ◽  
Chemical Accidents ◽  
Agent Based ◽  
Chemical Accident

Large-scale chemical accidents that occur near areas with large populations can cause significant damage not only to employees in a workplace but also to residents near the accident site. Despite the increasing frequency and severity of chemical accidents, few researchers have argued for the necessity of developing scenarios and simulation models for these accidents. Combining the TRANSIMS (Transportation Analysis and Simulation System) agent-based model with the ALOHA (Areal Location of Hazardous Atmospheres) dispersion model, this study aims to develop a modeling framework for simulating emergency evacuations in response to large-scale chemical accidents. The baseline accident scenario assumed the simultaneous leakage of toxic chemicals from industrial complexes near residential areas. The ALOHA model results showed that approximately 60% of residents in the scenario’s city were required to evacuate their homes. The majority of evacuees completed their evacuations within 5 h in the baseline scenario (evacuating maximum number of private vehicles without any intervention), while the distribution of the population and street network density caused geographical variability in clearance time. Clearance time can be significantly reduced by changing both the evacuees’ behaviors and the evacuation policy, which suggests the necessity for proper public intervention when the mass evacuation of residents is required due to chemical accidents.

scholarly journals Towards predicting noise-power-distance curves for propeller and rotor powered aircraft

2021 ◽  
Vol 263 (3) ◽  
pp. 3909-3920
Author(s):  
Daniel Amargianitakis ◽  
Rodney H. Self ◽  
Antonio J. Torija ◽  
Anderson R. Proença
Keyword(s):  
Scaling Laws ◽  
Noise Exposure ◽  
Power Distance ◽  
General Aviation ◽  
Noise Power ◽  
Baseline Scenario ◽  
Noise Sources ◽  
Propulsion Systems ◽  
Level Model ◽  
High Level

Propeller and rotor based propulsion systems are the dominating choice of power delivery system in the upcoming Urban Air Mobility market. Fully electric air-taxis (car sized vehicles with Vertical Take-off and Landing, VTOL, capabilities) concepts are using the benefits of the scalable properties of electric motors to distribute propulsor units all over the airframe. The large variety of concepts and configurations of these vehicles poses a serious issue in predicting noise generated on the ground. The need for a high-level model to aid in acoustic decision making is evident. Through the demonstrated methodology of computationally deriving Noise - Power - Distance curves for conventional turbo fan aircraft, this paper delivers the capability of dealing with propeller propulsion systems and the associated propeller tonal noise sources to generate the NPDs and therefore noise exposure maps. The aims can be broken down into two objectives: a) demonstrate the capabilities of the proposed propeller harmonics noise scaling laws to calculate noise variation from a baseline scenario and b) incorporate the scaling components into the larger capability of producing noise exposure contours, by the means of computationally deriving NPD curves for propeller powered aircraft. Preliminary NPD curves for General Aviation sized propeller power aircraft are generated and discussed.

scholarly journals Multi-Domain Design Structure Matrix Approach Applied to Urban System Modeling

Urban Science ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 28
Author(s):  
Peter Hoffmann ◽  
Yutaka Nomaguchi ◽  
Keishiro Hara ◽  
Kana Sawai ◽  
Ingenuin Gasser ◽  
...  
Keyword(s):  
Conceptual Model ◽  
Urban System ◽  
Well Being ◽  
Integrated Model ◽  
Urban Morphology ◽  
Design Structure Matrix ◽  
Modeling Framework ◽  
Structure Matrix ◽  
Modeling Approaches ◽  
Design Structure

Modeling the urban system for urban health and well-being with the aim of finding ways to optimize the well-being of urban dwellers is a complex task. Different modeling approaches that consider specific parts of the urban system, e.g., environmental stressors, urban society, and urban morphology, need to be integrated. The conceptual model of health-related urban well-being (UrbWellth) has been constructed to provide a structure for an integrated modeling framework. However, interfaces between the different modeling approaches were not sufficiently identified until now. The challenge to specify and operationalize these interfaces is met by using the Design Structure Matrix (DSM) concept, which is widely used in design engineering. It is used here to identify necessary interfaces within the urban system by determining the relevant interface variables and processes. The conceptual model for UrbWellth is used to construct a DSM. The results of a clustering of this UrbWellth-based DSM reveal that the structure of the conceptual model is indeed suitable to serve as a basis for an integrated model. Further, a Multi-Domain DSM (MDDSM), which is an extension of the DSM based on expert knowledge from individual modelers, identified the interface variables for the integrated model components as well as the processes for which different modeling approaches need to be coordinated. Moreover, the approach based on MDDSM identified processes that are not yet covered by the available modeling approaches.

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