Global ETD Search

31	Reduced-Order Rotor Performance Modeling for Martian Flight Vehicle Design Bensignor, Isaac Solomon 26 October 2022 (has links) No description available. Aerospace Engineering Martian rotorcraft flight Mars helicopter Mars aerodynamics blade element momentum theory Mars optimized airfoils compressible, low Reynolds number flow ultra-low Reynolds number flow low Reynolds number flow
32	Development and Implementation of Rotorcraft Preliminary Design Methodology using Multidisciplinary Design Optimization Khalid, Adeel S. 14 November 2006 (has links) A formal framework is developed and implemented in this research for preliminary rotorcraft design using IPPD methodology. All the technical aspects of design are considered including the vehicle engineering, dynamic analysis, stability and control, aerodynamic performance, propulsion, transmission design, weight and balance, noise analysis and economic analysis. The design loop starts with a detailed analysis of requirements. A baseline is selected and upgrade targets are identified depending on the mission requirements. An Overall Evaluation Criterion (OEC) is developed that is used to measure the goodness of the design or to compare the design with competitors. The requirements analysis and baseline upgrade targets lead to the initial sizing and performance estimation of the new design. The digital information is then passed to disciplinary experts. This is where the detailed disciplinary analyses are performed. Information is transferred from one discipline to another as the design loop is iterated. To coordinate all the disciplines in the product development cycle, Multidisciplinary Design Optimization (MDO) techniques e.g. All At Once (AAO) and Collaborative Optimization (CO) are suggested. The methodology is implemented on a Light Turbine Training Helicopter (LTTH) design. Detailed disciplinary analyses are integrated through a common platform for efficient and centralized transfer of design information from one discipline to another in a collaborative manner. Several disciplinary and system level optimization problems are solved. After all the constraints of a multidisciplinary problem have been satisfied and an optimal design has been obtained, it is compared with the initial baseline, using the earlier developed OEC, to measure the level of improvement achieved. Finally a digital preliminary design is proposed. The proposed design methodology provides an automated design framework, facilitates parallel design by removing disciplinary interdependency, current and updated information is made available to all disciplines at all times of the design through a central collaborative repository, overall design time is reduced and an optimized design is achieved. All at Once Aeronautical design standards Blade element theory Contributing analyses Concurrent engineering Collaborative optimization Design structure matrix Fixed point iteration Genetic algorithms Global sensitivity equation Multidisciplinary design analysis Multidisciplinary design optimization Optimizer based decomposition Overall evaluation criteria Request for proposal Response surface equation Simultaneous analysis and design Sequential quadratic programming System sensitivity analysis Total quality management
33	Aerodynamics of the Maple Seed Desenfans, Philip January 2019 (has links) (PDF) Purpose - The paper presents a theoretical framework that describes the aerodynamics of a falling maple (Acer pseudoplatanus) seed. --- Methodology - A semi-empirical method is developed that provides a ratio stating how much longer a seed falls in air compared to freefall. The generated lift is calculated by evaluating the integral of two-dimensional airfoil elements using a preliminary falling speed. This allows for the calculation of the definitive falling speed using Blade Element Momentum Theory (BEMT); hereafter, the fall duration in air and in freefall are obtained. Furthermore, the input-variables of the calculation of lift are transformed to require only the length and width of the maple seed. Lastly, the method is applied to two calculation examples as a means of validation. --- Findings - The two example calculations gave percentual errors of 5.5% and 3.7% for the falling speed when compared to measured values. The averaged result is that a maple seed falls 9.9 times longer in air when released from 20 m; however, this result is highly dependent on geometrical parameters which can be accounted for using the constructed method. --- Research limitations - Firstly, the coefficient of lift is unknown for the shape of a maple seed. Secondly, the approximated transient state is yet to be verified by measurement. --- Originality / Value - The added value of this report lies in the reduction of simplifications compared to BEMT approaches. In this way a large amount of accuracy is achieved due to the inclusion of many geometrical parameters, even though simplicity is maintained. This has been accomplished through constructing a simple three-step method that is fundamental and essentially non-iterative. ddc:620 info:eu-repo/classification/ddc/629.13 Aerodynamik Ahorn Auftrieb Strömungsabriss Aerodynamics Maple Lift (Aerodynamics) Stalling (Aerodynamics) Aerodynamisches Profil Anstellwinkel Freier Fall Bergahorn Samen Evolutionsbiologie Aerofoils Angle of attack (Aerodynamics) Acer pseudoplatanus Seeds Evolution (Biology) Blade Element Momentum Theory BEMT free fall post-stall chord twist camber autorotation
34	Design and Experimentation of Darrieus Vertical Axis Wind Turbines Gonzalez Campos, Jose Alberto 07 September 2020 (has links) No description available. Energy Mechanical Engineering Fluid Dynamics Engineering Aerospace Engineering Vertical Axis Wind Turbines - VAWT Straight-Bladed Helical-Bladed Troposkien-Bladed Darrieus Wind Turbines MPPT Control Wind Tunnel Experimentation Blade Element Theory - BEM Double Multiple Streamtube Model - DMST Free-Vortex Wake Model - LLFVW

Page generated in 0.3277 seconds