Winding number based automatic mesh generation algorithm for hydrogen analysis code GASFLOW-MPI

<div class="section abstract"><div class="htmlview paragraph">Prediction of in-cylinder flows and fuel-air mixing are two fundamental pre-requisites for a successful simulation of direct-injection engines. Over the years, many efforts were carried out in order to improve available turbulence and spray models. However, enhancements in physical modeling can be drastically affected by how the mesh is structured. Grid quality can negatively influence the prediction of organized charge motion structures, turbulence generation and interaction between in-cylinder flows and injected sprays. This is even more relevant for modern direct injection engines, where multiple injections and control of charge motions are employed in a large portion of the operating map. Currently, two different approaches for mesh generation exist: manual and automatic. The first makes generally possible to generate high-quality meshes but, at the same time, it is very time consuming and not completely free from user errors. Automatic mesh generation is very fast, but does not easily allow to align grid with flow and spray in regions of interest, for instance where fuel is injected or where the air flow is confined between pipe walls and thigh gaps (intake and exhaust head ducts and valve gaps). Within this context, the authors have developed a novel approach for automatic mesh generation, where both mesh quality and flow alignment are taken into account. Such methodology has been incorporated into the Lib-ICE code, which is based on the OpenFOAM technology. On the basis of combustion chamber details and/or user specified parameters (piston bowl points, injector direction, squish height, valve lift diagram,…), body fitted, high quality grids are automatically generated to perform full-cycle or compression/combustion simulations. To assess the proposed approach, two direct-injection engines were simulated. The first is Diesel fueled and only compression and combustion phases are simulated, showing the advantages of a spray-oriented grid, compared to a conventional Cartesian one, in terms of prediction of fuel-air mixing and combustion process. The second one is a gasoline, direct-injection engine. In this case full-cycle simulations were performed and computed flow field data were compared with optical experimental ones.</div></div>

It is important to establish an integrated CAD system for mechanical engineering. The geometric model is constructed with primitives, such as wire frame, surface and solid on this system. The finite element model is induced from the substructure, which is a component of the geometric model. After the extraction of the substructure from the model, the mesh for the finite element analyses is automatically generated against the substructure. An approach to automatic mesh generation is discussed on this paper, based upon the techniques of interpolation with the blending function, originally developed for geometric modeling. But, the blending function may produce unexpected results when the mesh is generated, due to the nature of the algorithm. In order to conclude with expected results for automatic mesh generation, and accuracy-fitting method is introduced.

A fuzzy logic knowledge-based approach, FUZZYMESH, for finite element mesh generation and analysis is presented. The proposed approach initiates the adaptive process with a high quality initial mesh that is more refined around the critical points/regions in the problem domain. In order to create high quality initial meshes, the heuristic knowledge, past experience, common sense, and ad hoc methods of finite element specialists are incorporated into the knowledge base of the fuzzy system. Using the linguistic variable concept and approximate reasoning techniques, the fuzzy system makes expert decisions about the initial mesh design by considering the geometric information, as well as the boundary and loading conditions. The decision process includes the determination of priority of critical points/regions and the prediction of mesh sizes for them. According to the mesh size information, a near-optimal initial mesh is created with an automatic mesh generator that is based on the advancing front mesh generation technique. The performance of the proposed approach was measured and evaluated in terms of efficiency and accuracy. The evaluation included comparison between the results of a code based on the proposed fuzzy logic knowledge-based approach, FUZZYMESH, and the conventional approach, which starts the finite element analysis with different meshes, by solving various problems. The global as well as local errors of different solutions were examined and compared. The CPU times for different approaches to achieve a particular accuracy were also measured and compared. The results showed that due to better quality of initial meshes, FUZZYMESH results in lower levels and more accurate error estimates. In turn, the proposed approach is able to solve the problem with a more accurate solution at less cost.

A methodology for the automatic mesh generation of quadrilateral elements is proposed. The methodology is based on the facts that (i) a region can always be subdivided entirely into quadrilaterals if the polygon which forms the boundary of the region has an even number of sides, (ii) a quadrilateral can be formed by two triangles which share a common side. By taking advantage of the techniques developed in an existing automatic triangular mesh generator, quadrilateral meshes can be generated according to the distribution of user specified element size over the domain of interest. In particular, an automatic quadrilateral mesh generator based on the advancing front technique for triangular mesh generation1 is described. Techniques to improve the quality of the generated quadrilateral meshes are introduced. The robustness and versatility of the mesh generator are demonstrated by a variety of examples.

Extended-Reality Technologies: An Overview of Emerging Applications in Medical Education and Clinical Care.

The rapid development of virtual and augmented reality technologies is currently taking place in almost all spheres of activity. Elements of virtual and augmented reality are used in such areas as education, medicine, transport, gaming, tourism and others. The active spread of these technologies causes the emergence of special competencies in the IT labor market and, as a result, the formation of new professions.Many Russian universities are training students in IT training areas. Specialization in the development of computer games and virtual reality applications has begun recently. The provision of practical classes is accompanied by specific tasks, which gives students the opportunity to improve the use of software and technical devices.The relevance of the research is determined by the current demand for the use of the latest technologies by IT developers in the field of creating computer games. Today, technologies that provide a player’s immersion in virtual reality are becoming more and more popular. One of these technologies is a suit with wearable sensors that track a person’s position in space in real time. However, there are quite a few real described projects in the literature and on the Internet. This study examines the process of developing a task for creating a game application using virtual reality technology: a suit with wearable sensors for teaching students.Materials and methods of research. Timely identification of the needs of the IT market in personnel training allows educational organizations to form new training programs of different levels of training. This approach makes it possible to target the educational and methodological materials being developed to use the latest achievements in the development of the field under study.Using a systematic approach, the study characterizes virtual reality suits and sensors for monitoring the position in the user’s space. Thus, the goal of the task was to ensure the immersiveness and convenience of interaction between the player and the game environment.Based on materials on software, position sensors in space, the approach of pedagogical design was applied and the procedure was formed for a practical task, reflecting the relevant competencies.Results. The study was conducted on the basis in the framework of laboratory and practical work of students, as well as at a real enterprise. Training in the new profile of the direction of training “Applied informatics” is fully equipped with all the latest technologies in this field. As a result of the work, the content of the practical task was developed.Real development of virtual and augmented reality applications is conducted jointly with students. Almost all projects used a suit with body sensors.Conclusion. Our study examines in detail the process of developing an application using a suit with wearable sensors for further training of students. Based on the results, work can be carried out on real projects for any field. Based on the research materials, it is planned to issue a textbook for students with the profile of developing computer games and virtual / augmented reality applications.

2D automatic body-fitted structured mesh generation using advancing extraction method

Purpose Automatic mesh generation is still a challenge problem for combustion fluid dynamics simulations because of the high-quality requirement and complexity of geometries. This paper aims to find an efficient automatic analysis model creation and mesh generation method to save the time for pre-processing in numerical simulations. Design/methodology/approach Based on the previous work, we explore effective model processing and mesh generation methods from practical engineering applications. Considering the automation and high quality requirement, we construct an automatic mesh generation procedure for combustion fluid dynamics problems. Findings The numerical results show that the procedure we proposed in this paper can automatically generate high quality mesh for combustion fluid dynamics simulations. The strategy of fluid model construction is time-saving and with high-precision. The mesh generation method in our procedure is automatic and efficient. Practical implications The procedure proposed in this paper is applicable to the practical engineering application model, such as aircraft simulation, aeroengine simulation and so on. The procedure has been integrated into an numerical simulation software. Originality/value The method proposed in this paper has very practical application value. It can be used in the practical application and saves a lot of manual processing time for numerical stimulation specialists.

본 연구는 디지털 기술이 고도로 발달하고 가상현실(VR)의 기술이 상용화되면서, 유물의 보존과 연구 및 전시에 중점을 두었던 전통적인 개념의 박물관이 직면하게 된 여러 가지 쟁점에 주목하여 가상현실 기술이 박물관을 어떻게 변화시키고 있으며 변화의 주된 동인은 무엇인지 고찰해 보는 것을 목적으로 한다. 어느 장소에서나 실제 공간에서 보고 느끼는 것과 같은 가상현실을 체험할 수 있는 기기는 게임 산업을 필두로 하여 문화콘텐츠 산업의 전반에서 본격적으로 대중들에게 상용화되기 시작되었으며, 이런 현실에 맞추어 세계의 유수 박물관들은 2015년을 전후로 앞 다투어 새로운 형식의 전시를 제안하거나 사이버 박물관의 콘텐츠를 새롭게 다듬고 있는 실정이다. 본 연구는 박물관에 가상현실 기술이 본격적으로 활용되기 시작한 2015년 이후 박물관에 나타나고 새로운 시도와 전략을 중심으로, 기술의 발전으로 인해 박물관의 역할이 어떻게 달라질 것인지에 대해 학제적인 관점을 통해 고찰해본다. 본 연구는 세계 주요박물관들의 주목할 만한 VR기술 활용 방식을 분석하여, VR영상 콘텐츠가 유물 및 박물관이라는 공간과 맺는 관계에 따라 활용 유형을 네 가지로 분류하였다. ①박물관의 공간을 모두 VR로 체험할 수 있게 하는 사이버 뮤지엄의 전략 ②유물의 시대를 가상으로 재현하여 전시 오브제를 재맥락화 ③전시 작품 혹은 콘텐츠를 확장시키는 새로운 작품으로서 VR ④가상의 공간을 재현하는 사례가 그것이다. 0차원의 디지털로 기술적 형상을 구현함으로써, 다시 라스코 동굴벽화의 시대와 같은 마술적, 제의적 이미지가 도래할 것이라 예견했던 빌렘 플루서의 이론은 오늘날 VR기술이 보여주는 마법과 같은 공간의 재현에 정확히 부합하는 듯이 보인다. 본 연구는 VR기술의 상용화는 박물관이 선사했던 원작의 아우라를 새로운 방식으로 확장시킬 것임을 보여주며, 앞으로 박물관에서는 플루서가 말하는 현대적 ‘뮈토스’의 체험을 가능케 하는 새로운 VR 전시콘텐츠의 기획이 불가피하다는 점을 보여준다.This study focuses on the ways of using VR technology by museums, one of the important issues faced by traditional museums. With rapid development of digital technology including virtual reality(VR) technology, many museums of the world presented new forms of exhibitions or refined cyber museum contents especially since 2015. This study tries to examine theses new attempts and strategies through the interdisciplinary perspective. According to our case studies, the ways of using VR technology could be classified by 4 types of strategy. ① Cyber museum s strategy to give experience of visiting virtually all the spaces of museum such as VR guide tour ② Recontextualization strategy by reproducing virtually the era and the environments where exhibits originally existed ③ VR content as a new media art to expand existing exhibition ④ Virtual exhibition by making virtual space through gamification. By embodying a technical dimension in zero-dimensional digital form, Vilém Flusser s theory predicted that magical and ritual images’ era, such as the era of Lasco s cave painting, would come again. Based on the theory of Flusser, this study shows that the development of ways of using VR technology will continue to expand the aura of original exhibits in a new way, and allow us to experience modern mythos.

Virtual Reality (VR) technology has emerged as one of the most transformative and promising innovations in contemporary education. VR refers to a sophisticated technology that generates artificial environments, offering users an immersive experience that simulates presence within a digitally constructed, three-dimensional world. Using devices such as VR headsets, students are able to engage with these virtual environments in a manner that replicates real-world interactions, thereby providing access to experiences that would otherwise be difficult or impossible to attain in reality. This study seeks to investigate the utilization and acceptance of Virtual Reality (VR) technology among teachers and students in schools across the state of Perlis. In the context of a rapidly advancing digital era, VR offers unprecedented opportunities for education by facilitating interactive, immersive learning experiences. However, the extent of readiness and acceptance of this innovative technology among teachers and students in Perlis remains uncertain. Employing a quantitative research methodology, this study gathered data through the administration of structured questionnaires. The results indicate that both students and teachers exhibit a strong interest in integrating VR technology into the educational landscape. The respondents demonstrate a foundational understanding of VR and express confidence that its application in schools can significantly enhance learning outcomes. Despite the widespread enthusiasm for incorporating VR into teaching and learning processes, several critical challenges must be addressed to facilitate its adoption. These challenges include inadequate access to necessary equipment, insufficient training, and a lack of robust infrastructure support. This study offers a set of strategic recommendations aimed at overcoming these obstacles and fostering the broader acceptance and implementation of VR technology in the schools of Perlis.

Visual communication experiences have been revolutionized by virtual reality (VR) technology, offering users immersive and captivating interactions with digital content. Through VR headsets and immersive environments, users can engage with visual content in unprecedented ways, feeling as though they are physically present within the digital space. Whether exploring virtual art galleries, immersive storytelling experiences, or interactive visualizations, VR technology provides users with a sense of presence and agency, enhancing their connection to the content. Furthermore, VR enables creators to design highly engaging and interactive visual experiences that transcend traditional media formats, allowing for innovative storytelling techniques and immersive narratives. This paper presents the design of a novel visual communication experience leveraging virtual reality (VR) technology enhanced by Multi-Spectral Multi-Point Co-Ordination (MSMPC). The proposed design aims to create immersive and engaging visual experiences that transcend traditional media formats. Through simulated experiments and empirical validations, the effectiveness of the MSMPC-enhanced VR-based visual communication experience is evaluated. Results demonstrate significant improvements in user engagement, immersion, and satisfaction compared to conventional approaches. The users interacting with the MSMPC-enhanced VR experience reported a 40% increase in immersion levels and a 25% improvement in overall satisfaction ratings. Additionally, the design enabled creators to optimize visual storytelling techniques based on real-time user feedback and performance data, leading to more impactful and effective communication. These findings highlight the potential of MSMPC in enhancing visual communication experiences based on VR technology, paving the way for innovative and immersive storytelling in various domains.

In this paper, we present the development and application of a two-dimensional, automatic unstructured mesh generator for shallow water models called Admesh. Starting with only target minimum and maximum element sizes and points defining the boundary and bathymetry/ topography of the domain, the goal of the mesh generator is to automatically produce a high-quality mesh from this minimal set of input. From the geometry provided, properties such as local features, curvature of the boundary, bathymetric/topographic gradients, and approximate flow characteristics can be extracted, which are then used to determine local element sizes. The result is a high-quality mesh, with the correct amount of refinement where it is needed to resolve all the geometry and flow characteristics of the domain. Techniques incorporated include the use of the so-called signed distance function, which is used to determine critical geometric properties, the approximation of piecewise linear coastline data by smooth cubic splines, a so-called mesh function used to determine element sizes and control the size ratio of neighboring elements, and a spring-based force equilibrium approach used to improve the element quality of an initial mesh obtained from a simple Delaunay triangulation. Several meshes of shallow water domains created by the new mesh generator are presented.

RETRACTED: Development and application of VR course resources based on embedded system in open education

An ANN-based element extraction method for automatic mesh generation

Public space scenes are being transformed by virtual reality (VR) technology, offering immersive and interactive experiences that redefine how people engage with their surroundings. Through VR simulations, users can explore and interact with virtual public spaces in ways that were previously impossible. From virtual parks and plazas to digital replicas of iconic landmarks, VR technology allows users to experience the ambiance and atmosphere of public spaces from the comfort of their own homes. Moreover, VR enables designers and planners to experiment with different layouts, amenities, and features, facilitating participatory design processes and community engagement. This paper presents a visual design and evaluation framework for public space scenes using virtual reality (VR) technology, enhanced by Virtual Parallel Edge Hashing Computing (VPE-HC). The framework aims to optimize the design and user experience of public spaces by leveraging VR technology to create immersive and interactive simulations. Through simulated experiments and empirical validations, the effectiveness of the VPE-HC-enhanced VR-based design and evaluation process is evaluated. Results demonstrate significant improvements in user satisfaction, engagement, and usability compared to traditional design methods. For instance, users interacting with public space scenes designed using VPE-HC reported a 40% increase in perceived safety and a 25% improvement in overall satisfaction ratings. Additionally, the framework enabled designers to optimize spatial layouts and amenities based on real-time user feedback and performance data, leading to more effective and user-centric design solutions. These findings underscore the potential of VPE-HC in enhancing the visual design and evaluation of public space scenes based on VR technology, facilitating more inclusive and user-friendly urban environments.