scholarly journals Coordinate Free Programming of Computational Fluid Dynamics Problems

2000 ◽  
Vol 8 (4) ◽  
pp. 211-230 ◽  
Author(s):  
Philip W. Grant ◽  
Magne Haveraaen ◽  
Michael F. Webster
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Software Engineering ◽  
Software Development ◽  
Coordinate Systems ◽  
Scientific Applications ◽  
Software Modules ◽  
The Difference ◽  
Engineering Practices ◽  
Dynamics Problems

It has long been acknowledged that the development of scientific applications is in need of better software engineering practices. Here we contrast the difference between conventional software development of CFD codes with a method based on coordinate free mathematics. The former approach leads to programs where different aspects, such as the discretisation technique and the coordinate systems, can get entangled with the solver algorithm. The latter approach yields programs that segregate these concerns into fully independent software modules. Such considerations are important for the construction of numerical codes for practical problems. The two approaches are illustrated on the coating problem: the simulation of coating a wire with a polymer.

scholarly journals Towards Specific Software Engineering Practices for Early-Stage Startups

2020 ◽  
pp. 18-22
Author(s):  
Jorge Melegati ◽  
Rafael Chanin ◽  
Afonso Sales ◽  
Rafael Prikladnicki
Keyword(s):  
Software Engineering ◽  
Software Development ◽  
Early Stage ◽  
Position Paper ◽  
Market Driven ◽  
Engineering Practices ◽  
Software Development Practices

Abstract In this position paper, our goal is to argue the need for specific software development practices to early-stage startups. In order to reach this goal, we discuss the consequences of innovative and market-driven contexts, which are two of the key elements when describing software startups. We also argue that these practices could be applied to innovative initiatives within established companies since they share similar characteristics and challenges as those from startups.

Prediction of the Flotsam Component in a Gas-Fluidized Bed of Two Dissimilar Solids

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Alberto Di Renzo ◽  
Francesco P. Di Maio ◽  
Vincenzino Vivacqua
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Simple Model ◽  
Discrete Element Method ◽  
Fluidized Bed ◽  
Fluidized Beds ◽  
Computational Simulations ◽  
The Difference ◽  
Gas Fluidized Beds

In the present paper the segregating behaviour of solids of different size and density in gas-fluidized beds is studied. In particular, the attention is focussed on pairs composed of a bigger/less dense species and a smaller/denser species. Typical industrial examples of such combinations are encountered in fluidized beds of biomass/sand mixtures. Their behaviour is not easily predictable, as the segregation tendency promoted by the difference in density is counteracted by the difference in size. While typically the denser component is expected to appear predominantly at the bottom of the fluidized bed, experiments on mixtures exhibiting the reverse behaviour have been reported (e.g. Chiba et al., 1980).A simple model to predict the segregation direction of the components, i.e. which species will segregate to the top of the bed (the flotsam), depending upon their difference in properties (size, density) and the mixture composition, is discussed. The predicted behaviour is compared with experimental data available in the literature and agreement is found for the majority of them. For one mixture, experiments are conducted as well as computational simulations based on the combined Discrete Element Method and Computational Fluid Dynamics (DEM-CFD) approach. This allows investigating how an initially mixed bed upon suspension evolves as a result of the segregation prevalence in the bed.

scholarly journals A Study on the Efficient Method for the Solution of the Saha Equation in the Numerical Simulation of Capillary Discharge

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Hengzhu Liu ◽  
Cheng Wu ◽  
Fengjiang An ◽  
Shasha Liao
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Transport Coefficients ◽  
Capillary Discharge ◽  
Dimensional Problem ◽  
Initial Value ◽  
One Dimensional ◽  
Saha Equation ◽  
Dynamics Problems

In the numerical simulation of capillary discharge for the Electrothermal (ET) or ET-chemical (ETC) launch system, one needs to solve the Saha equation to determine the composition of plasma for the transport coefficients. This would cause a relatively longer simulation runtime compared with conventional computational fluid dynamics problems. In this paper, the relatively difficult multidimensional problem of solving the Saha equation is transformed into a one-dimensional problem in the simulation of capillary discharge by constructing an iteration equation about temperature. A coefficient is introduced to ensure the convergence of this iteration equation. In order to improve the computational efficiency, this coefficient is further optimized and the methods of setting the iteration initial value dynamically are introduced. Several simulation tests are conducted to study the performance of these two methods. The results show that the simulation runtime could be significantly reduced with the methods presented in this paper.

THE APPLICATION OF MODERN SOFTWARE ENGINEERING PRACTICES TO CONTROL ENGINEERING

2003 ◽  
Vol 02 (01) ◽  
pp. 127-141 ◽  
Author(s):  
BRAIN A. BERENBACH ◽  
PETER R. SPOOL ◽  
DIETER BITTERLE
Keyword(s):  
Software Engineering ◽  
Software Development ◽  
Cost Reduction ◽  
Maturity Model ◽  
Development Environment ◽  
Control Engineering ◽  
Capability Maturity ◽  
Custom Software ◽  
Engineering Practices

Over the years, control systems have become increasingly dependent on custom software. As hardware has gotten cheaper, attention has focused on improving the processes associated with developing control system software by using approaches such as the Software Engineering Institute's Capability Maturity Model (CMM),1,2 and enabling reuse and long term cost reduction with component-based software development. This paper discusses the application of the CMM to the software process used in control engineering and the use of component based software development. We also discuss some advanced features of the Siemens SIMATIC STEP 7 Universal Development Environment that provides the tools to plan, configure, evelop, test, troubleshoot, document and support not only PLC programs, but also entire auto, ation projects. STEP 7 also enables and support process improvement and component-based software development.

scholarly journals Laboratory and Computational Fluid Dynamics Investigation of Homogenization in a Tank Stirred by External Pump

2019 ◽  
Vol 64 (4) ◽  
pp. 457-468
Author(s):  
Janka Bobek ◽  
Attila Egedy ◽  
Dóra Rippel-Pethő
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Operating Time ◽  
Experimental Device ◽  
Sampling Point ◽  
Concentration Changes ◽  
The Difference ◽  
Sharp Concentration ◽  
Experimental Fluid ◽  
Stratified Liquid

The scope of this study was to investigate the homogenization of a two-layer stratified liquid in a tank where liquid stirring was achieved by carrying out external recirculation. Furthermore, the aim of the research was to observe the effect of the height of the outlet during the time of mixing one. The experimental fluid was two-layer, density stratified liquid. From the perspective of homogeneity, the effect of the height of the outlet was investigated in laboratory. Moreover, the experimental device was modeled in CFD. In simulation examination, laminar - and k-ε-model were used, and the influence of the outlet position was observed. The difference was remarkable in the first part of the measurement caused by the presence of sharp concentration variation in the tank. After the operating time, the expected homogeneity was fulfilled at the outlet in all cases. Regarding of CFD research, the results suggest that the laminar model is more effective to describe the concentration changes at the sampling point in the tank investigated.

Software Development Governance

2011 ◽  
pp. 315-332 ◽  
Author(s):  
Nagehan Pala Er ◽  
Cengiz Erbas ◽  
Bahar Çelikkol Erbas
Keyword(s):  
Software Engineering ◽  
Software Development ◽  
Transaction Cost ◽  
Configuration Management ◽  
Governance Structure ◽  
Management Approach ◽  
Software Modeling ◽  
Management Tools ◽  
Dependency Structure ◽  
Software Modules

Software development governance can be defined as the application of “governance” in software engineering in order to increase the probability of success in the level of individual projects as well as in the level of the organization comprising many interrelated projects. The topic deserves an interdisciplinary perspective, as the general subject of governance has been analyzed quite extensively under the field of Transaction Cost Economics. This interdisciplinary approach enabled the identification of three main modes of governance for software engineering, namely: top-down governance, bottom-up governance and reuse governance, each having unique transaction cost characteristics. To be cost effective, (1) the organizations should adapt the right governance structure for their projects based on their characteristics, and (2) the software development tools should support and be in alignment with the underlying governance structure. In this chapter, we briefly overview the first premise and then outline an approach to address the second premise, specifically tackling the issue of tools integration, for software modeling and configuration management tools. We use Dependency Structure Matrix (DSM) to represent the mapping between governance structures and software modules, propose a configuration management approach for each mode of software governance, and demonstrate a successful integration using Lattix LDM, IBM Rational ClearCase and IBM Rational Rhapsody, three broadly available tools in the software industry.

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