INCAS Bulletin最新文献

{"title":"Simulation of pulsatory liposome working using a linear approximation for transmembrane pore dynamics","authors":"D. Popescu, D. Constantin, V. I. Niculescu","doi":"10.13111/2066-8201.2024.16.1.9","DOIUrl":"https://doi.org/10.13111/2066-8201.2024.16.1.9","url":null,"abstract":"This paper presents an analytical solution of the differential equations describing the pulsatory liposome dynamics. We consider a unilamellar liposome filled with an aqueous solution of osmotic solute inserted in a hypotonic aqueous medium. Due to the osmosis process the liposome has a cyclic evolution. The lipid vesicle swells to a critical size, at which point a transbilayer pore suddenly appears. Part of the internal solution leaks through this pore. The liposome relaxes and returns to the initial size. The swelling starts again and the liposome goes through a periodical process. The swelling of the liposome is described by a differential equation. The appearance of the pore changes the evolution of the liposome. The internal solution comes out through the pore and the liposome starts its deflation (relaxation). The evolution of the pore has two phases: first, the radius of the pore increases to its maximum value, then the radius decreases until it disappears, and the liposome reaches its initial size. During each cycle, the liposome will release a quantity (a pulse) of the solution from its interior. All the processes which contribute to the liposome relaxing and its coming back to the initial size are described by three differential equations. This system of differential equations can be integrated using numerical methods. The functions – which model our biological engine in three stages, are as follows: R(t) - the liposome radius, r(t) - the pore radius, C(t) - solute concentration, Q(t) - the osmotic solute amount inside the liposome. The graphs representing these functions contain important linear portions, which suggested a solution using analytical methods. Based on some analytical methods, we solve these equations, and their explicit solutions are validated by comparing with numerical results of previous studies.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140254760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Analysis of Convergent-Divergent Angles and Operating Conditions Impact on Rocket Nozzle Performance Parameters","authors":"Nabila Alili, Khacem Kaddouri, Salem Mokadem, Ahmed Alami","doi":"10.13111/2066-8201.2024.16.1.1","DOIUrl":"https://doi.org/10.13111/2066-8201.2024.16.1.1","url":null,"abstract":"Comprehensive numerical analysis was conducted to elucidate the exhaust performance of rocket engine nozzles. The study focused on unravelling the intricate relationship between convergence and divergence angles and their impact on the exhaust performance parameters, including velocity coefficient (cv), angularity coefficient (Ca), and gross thrust coefficient (Cfg). In contrast to conventional studies that focus mainly on the divergent section, this research delved into both convergent and divergent aspects of nozzle geometry. For the convergent section, a range of angles from 20° to 45° was systematically examined. For the divergent section, a wide spectrum of angles was explored, ranging from small (10°-13°), medium (14°-19°) and large (20°-25°) divergent angles. Further, we venture beyond geometry, investigating the influence of nozzle pressure ratio (NPR) on these key metrics. Realisable 𝑘𝑘−𝜀𝜀, enhanced wall traitement was used to simulate nozzle flow. The study identified the optimal convergent angle at 37.5°. The 15° diverging angle provides good overall performance, while the 23° angle strikes the ideal compromise: maximizing thrust and efficiency while minimizing weight and maintaining optimal performance.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140253222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive Analysis of Aircraft Dynamics Stability with SCSim: Integration and Assessment","authors":"Stefan Bogos, A. Chira, Ioan Petru Udrea, Valerian Marian Sandu, Theodor Draghici","doi":"10.13111/2066-8201.2023.15.4.4","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.4","url":null,"abstract":"This research presents a comprehensive analysis of the dynamic stability of aircraft using modules of the software named SCSim (Stability and Control Simulation Tool), which is dedicated to the analysis of aircraft stability and control. The stability of an aircraft can be examined in two directions: longitudinal and lateral. The ability to determine an aircraft's limits and handling qualities depends on its stability. This study report demonstrates a complete dynamic stability analysis using SCSim with aerodynamic input data from the commercial software Advanced Aircraft Analysis (AAA). SCSim is implemented within a common framework in MATLAB, adapted from a MATHCAD script, providing an easier way to enter user-defined input data, and introducing a set of new features. The study is divided into three main parts, each based on an analysis of stability. First, static stability is examined to understand how the system behaves when it is in equilibrium. Then, dynamic stability is assessed to understand how the system reacts to perturbations and disturbances. Finally, handling qualities systematically assess the dynamic modes of the aircraft's behavior and establish the levels of handling qualities. In this paper, a generic model of a propeller-driven aircraft is used for the study due to the availability of flight parameters, geometric, and aerodynamic data. The obtained results demonstrate the capabilities of the Stability and Control Simulation Tool (SCSim) in designing and analysing an aircraft's stability under various flight conditions and configurations, with validation using AAA.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphing concepts in the field of rotorcraft","authors":"Dorin Madalin Feraru, C. Larco, T. Grigorie","doi":"10.13111/2066-8201.2023.15.4.10","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.10","url":null,"abstract":"Drawing inspiration from avian creatures, aeronautical engineers strive to create an ideal wing design that can seamlessly perform in various flight conditions. Avian creatures, as well as bats and other flying organisms, exhibit a striking aptitude to adjust the lift produced by their wings, displaying the capacity to repeatedly tailor their wing configurations to match specific environmental conditions. An example of this is when their wings are tightly tucked during dives for hunting, or fully extended during gliding to conserve energy. Moreover, these organisms can manipulate the curvature and twist of their wings to maintain precise control over their aerial maneuvers. In contrast, engineers in the aircraft industry continue to rely on the standard, robust and structured “one-point design” approach, which remains the most practical and feasible method to apply. Nonetheless, advancements in technology have emerged to address long-standing challenges in wing manufacturing that were previously deemed insurmountable. This convergence of different technologies has given significant momentum and recognition to the field of “morphing discipline”. When considering an aircraft, shape changes primarily relate to the wing of a fixed-wing aircraft or the blade of a rotorcraft. The concept of achieving a \"smooth\" shape change stems from the crucial need for drag reduction and improved flow quality, resulting in improved overall performance. The state-of-the-art morphing concepts applied to rotorcrafts comprise a wide range of investigations aimed at improving performance. Looking ahead, the primary challenge for morphing technology will be to persuade the industry of its tangible benefits. This encompasses enhanced aerodynamic efficiency, minimized installation footprint when contrasted with conventional control surface mechanisms, reduced overall weight, and an equivalent standard of safety. This research provides an overview of the current development of different control devices and explores the impact of previous and continuous research endeavors in this field. Numerous ideas for managing airflow have been explored with the aim of enhancing the performance abilities of rotary-wing aircraft. These include active morphing in rotorcraft such as leading edge slats, trailing edge flaps, and passive morphing in rotorcraft such as variable rpm rotorcraft. The aim of these blade modifications is to achieve various desired effects such as increasing the maximum lift coefficient, reducing drag, and minimizing vibratory loads. Convincing the industry of these advantages will play a crucial role in shaping the future of morphing technology.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"VBA fatigue analysis program for metallic structural components preliminary design","authors":"Raul Cormoş, C. Neagoe, Miruna Ciolca, Anton Hadar","doi":"10.13111/2066-8201.2023.15.4.8","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.8","url":null,"abstract":"The main objective of this paper is to describe the creation and use of a fatigue analysis program written in VBA, designed for the preliminary sizing of metallic structural components used in aerospace applications, subjected to one or multiple fatigue loading cases. The VBA programing language was chosen because of its direct control over the most common spreadsheet computational program, Microsoft Excel. Metal fatigue analysis is an important type of analyses for modern structures. Fatigue failure accounts for around 80-90 percent of common structural failures, and therefore, a quick and reliable analysis is necessary so as to evaluate the structure’s bearing capacity to fatigue load. Due to the nature of the fatigue load and the importance of the structural component, such an analysis can be very time consuming, starting from the finite element model preparation and going through the actual analysis; thus, there is a need for a tool that can evaluate the stress data from the numerical simulation and give reliable information about the behavior of the structural component.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanical strength of the aircraft control chains in certain unusual cases","authors":"Cristian Tecuceanu, Dumitru Popovici, Mariana Popovici, Peter Kalmutchi","doi":"10.13111/2066-8201.2023.15.4.21","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.21","url":null,"abstract":"The paper focuses on certain specific occurrences involving sports aircraft and their mechanical flight control chains. Usually the flight controls and their control chains are subject of thorough checking procedures, but frequently such details are not observed or are easily ignored during the maintenance and airframe checking processes. The authors aim to provide information enabling proper training of flight crews, technical, and design staff/ personnel, allowing the avoidance of severe occurrences/ events caused by failures of the mechanical control chains. The analysis focuses on lighter aircraft, such as sports aircraft, which have full mechanical control chains.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138607100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep neural network modeling for CFD simulation of drone bioinspired morphing wings","authors":"F. Marin, D. Buruiana, Viorica Ghisman, M. Marin","doi":"10.13111/2066-8201.2023.15.4.12","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.12","url":null,"abstract":"In this paper we present a deep neural network modelling using Computational Fluid Dynamics (CFD) simulations data in order to optimize control of bioinspired morphing wings of a drone. Drones flight needs to consider variation in aerodynamic conditions that cannot all be optimized using a fixed aerodynamic profile. Nature solves this issue as birds are changing continuously the shape of their wings depending of the aerodynamic current requirements. One important issue for fixed wing drone is the landing as it is unable to control and most of the time consequences are some damages at the nose. An optimized shape of the wing at landing will avoid this situation. Another issue is that wings with a maximum surface are sensitive to stronger head winds; while wings with a small surface allowing the drone to fly faster. A wing with a morphing surface could adapt its aerial surface to optimize aerodynamic performance to specific flight situations. A morphing wing needs to be controlled in an optimized manner taking into account current aerodynamics parameters. Predicting optimized positions of the wing needs to consider (CFD) prior simulation parameters. The scenarios for flight require an important number of CFD simulation to address different conditions and geometric shapes. We compare in this paper neural network architecture suitable to predict wing shape according to current conditions. Deep neural network (DNN) is trained using data resulted out of CFD simulations to estimate flight conditions.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancing Airfoil Performance through Artificial Neural Networks and Genetic Algorithm Optimization","authors":"Mara-Florina Negoita, D. Crunțeanu, Mihai-Vlăduţ Hothazie, Mihai-Victor Pricop","doi":"10.13111/2066-8201.2023.15.4.17","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.17","url":null,"abstract":"As airfoil design plays a crucial role in achieving superior aerodynamic performances, optimization has become an essential part in various engineering applications, including aeronautics and wind energy production. Airfoil optimization using high-fidelity CFD, although highly effective, has proven itself to be time-consuming and computationally expensive. This paper proposes an alternative approach to airfoil performance assessment, through the integration of a deep learning algorithm and a stochastic optimization method. NACA 4-digit parametrization was used for airfoil geometry generation, to ensure feasibility and to reduce the number of input variables. An extensive dataset of airfoil performance parameters has been obtained using an automated CFD solver, laying the foundation for the training of an accurate and robust Artificial Neural Network, capable of accurately predicting aerodynamic coefficients and significantly reducing computational time. Due to the ANN’s predictive capabilities of efficiently navigating vast search spaces, it has been employed as the fitness evaluation method of a multi-objective Genetic Algorithm. Following the optimization process, the resulting airfoils demonstrate significant enhancements in aerodynamic performance and notable improvements in stall behavior. To validate their increased capabilities, a high-fidelity Computational Fluid Dynamics (CFD) validation was conducted. Simulation results demonstrate the approach’s efficacy in finding the optimum airfoil shape for the given conditions and respecting the imposed constraints.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of wind tunnel wall interference using homogeneous and measured boundary conditions","authors":"Mihaela Burghiu","doi":"10.13111/2066-8201.2023.15.4.5","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.5","url":null,"abstract":"The experimental results obtained in a wind tunnel must be subjected to a correction process which aims to eliminate the influence of the limited dimensions of the flow field around the model. This is necessary because the results must be independent of the characteristics of the laboratory where they were obtained, in order to ensure the quality of the parameters.The wall corrections are applied to the global quantities that characterize the undisturbed flow, such as the Mach number or the dynamic pressure, but they are also applied to the quantities related to the model, namely the global aerodynamic coefficients.Consequently the corrections will be applied to the global quantities of the undisturbed flow and therefore they will be transmitted to the aerodynamic quantities related to the model.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138606924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"L1 adaptive control design for the rigid body launch vehicle","authors":"Naji Anees Muqdad Naji, Adrian Stoica","doi":"10.13111/2066-8201.2023.15.4.16","DOIUrl":"https://doi.org/10.13111/2066-8201.2023.15.4.16","url":null,"abstract":"This paper investigates the use of an L1-adaptive controller to improve the performance of the Vega launch vehicle because the classical controller does not guarantee stability and tracking of the system in the transient. The L1-AC ensures uniformly bounded transient and steady-state tracking for both systems’ signals, input, and output. In this paper, we used the equations of the adaptation and the L1-norm with two filters, the first one is first-order order and the second filter is third-order, we used the large adaptive gain with the first filter, also used the low adaptive gain with the second filter, and after the analysis the result numerically we found the lambda with the first filter less than 1 and the lambda with second filter larger than lambda with the first filter. The L1 adaptive controller can generate a stable system response to track the control input and the system output, both in transient and steady-state because we selected the adaptive gain large with minimize lambda. It is noted that the system response for the L1 adaptive control configuration with the first filter, as compared with the system response with the second filter, has much better performances, both from the point of view of the overshoot and rise time.","PeriodicalId":37556,"journal":{"name":"INCAS Bulletin","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138607159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}