Semi-Implicit Time Integration in Limited Area Model

1989 ◽  
Author(s):  
Isidore Halberstam
Keyword(s):  
Time Integration ◽  
Implicit Time ◽  
Limited Area ◽  
Limited Area Model ◽  
Area Model ◽  
Implicit Time Integration

scholarly journals A nonmodal approach for time-integration of a barotropic limited area model

1997 ◽  
Vol 33 (9) ◽  
pp. 1-13 ◽  
Author(s):  
H.F. de Campos Velho ◽  
J.C.R. Claeyssen
Keyword(s):  
Time Integration ◽  
Limited Area ◽  
Limited Area Model ◽  
Area Model

scholarly journals Kinetic Simulation of Collisional Magnetized Plasmas with Semi-implicit Time Integration

2018 ◽  
Vol 77 (2) ◽  
pp. 819-849 ◽  
Author(s):  
Debojyoti Ghosh ◽  
Mikhail A. Dorf ◽  
Milo R. Dorr ◽  
Jeffrey A. F. Hittinger
Keyword(s):  
Time Integration ◽  
Implicit Time ◽  
Magnetized Plasmas ◽  
Kinetic Simulation ◽  
Implicit Time Integration

27 Years of Regional Cooperation for Limited Area Modelling in Central Europe

2018 ◽  
Vol 99 (7) ◽  
pp. 1415-1432 ◽  
Author(s):  
Yong Wang ◽  
Martin Belluš ◽  
Andrea Ehrlich ◽  
Máté Mile ◽  
Neva Pristov ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Central Europe ◽  
Regional Cooperation ◽  
Weather Prediction ◽  
Ensemble Forecasting ◽  
Limited Area ◽  
Member States ◽  
Limited Area Model ◽  
Area Model ◽  
Common System

AbstractThis paper describes 27 years of scientific and operational achievement of Regional Cooperation for Limited Area Modelling in Central Europe (RC LACE), which is supported by the national (hydro-) meteorological services of Austria, Croatia, the Czech Republic, Hungary, Romania, Slovakia, and Slovenia. The principal objectives of RC LACE are to 1) develop and operate the state-of-the-art limited-area model and data assimilation system in the member states and 2) conduct joint scientific and technical research to improve the quality of the forecasts.In the last 27 years, RC LACE has contributed to the limited-area Aire Limitée Adaptation Dynamique Développement International (ALADIN) system in the areas of preprocessing of observations, data assimilation, model dynamics, physical parameterizations, mesoscale and convection-permitting ensemble forecasting, and verification. It has developed strong collaborations with numerical weather prediction (NWP) consortia ALADIN, the High Resolution Limited Area Model (HIRLAM) group, and the European Centre for Medium-Range Weather Forecasts (ECMWF). RC LACE member states exchange their national observations in real time and operate a common system that provides member states with the preprocessed observations for data assimilation and verification. RC LACE runs operationally a common mesoscale ensemble system, ALADIN–Limited Area Ensemble Forecasting (ALADIN-LAEF), over all of Europe for early warning of severe weather.RC LACE has established an extensive regional scientific and technical collaboration in the field of operational NWP for weather research, forecasting, and applications. Its 27 years of experience have demonstrated the value of regional cooperation among small- and medium-sized countries for success in the development of a modern forecasting system, knowledge transfer, and capacity building.

An Explicit-Implicit Time Integration Approach for Finite Element Evaluation of Engine Load Following an FBO Event

2017 ◽  
Author(s):  
Yiliu Weng ◽  
Lipeng Zheng
Keyword(s):  
Finite Element ◽  
Extreme Event ◽  
Time Integration ◽  
Implicit Time ◽  
Engine Load ◽  
Load Following ◽  
Fine Mesh ◽  
Implicit Time Integration ◽  
Integration Approach ◽  
Fan Blade

Engine fan blade-off (FBO) is an extreme event that could well place the flight safety at risk. When it happens, the engine will experience high-velocity impact at first, and then enter into a “high-power” stage due to huge unbalance before coming to a steady state called “windmilling”. The analytical process for FBO can be split into two phases, one for impact simulation and the other for obtaining the FBO load to pylon. Typically, explicit method with fine mesh finite elements is used in the first phase, and implicit method with coarse meshes is adopted in the second one. In most cases, the only connection between these two analyses may be the unbalance level caused by FBO. More structural responses other than the unbalance level due to fan blade impact are actually ignored in the succeeding implicit analysis. Attempts have been made by Boeing, GE and MSC to integrate these two processes by adding some features in MD Nastran. Yet the intermediate binary files created and the restricted input entries make the integration process quite inflexible. This paper introduces an explicit-implicit time integration approach for finite element analysis of engine load following an FBO event. The proposed method attempts to connect the two stages more closely, yet in a more flexible manner. In this approach, the engine structural response under FBO obtained from explicit analysis is transferred to the implicit analysis, together with the unbalance level caused by blade loss. The necessity of the approach is discussed, and sensitivity analysis is conducted to understand the factors that play significant roles in the approach. As the models for explicit and implicit analyses are different in mesh sizes and scales, the authors also develop a tool that can interpolate the load information and further, smooth it to fit calculation. Finally, the approach is tested on a full engine model to show its applicability and advantages over the traditional method for load evaluation of FBO event.

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