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Validation of software for the calculation of aerodynamic coefficients : with a focus on the software package TornadoLópez Pereira, Ramón January 2010 (has links)
No description available.
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Validation of software for the calculation of aerodynamic coefficients : with a focus on the software package TornadoLópez Pereira, Ramón January 2010 (has links)
Several programs exist today for calculating aerodynamic coefficients that with some simplifications provide fast approximations of the values for a real aircraft. Four different programs were analyzed for this report: Tornado, AVL, PANAIR and a handbook-type preliminary method. In addition, ANSYS CFX was used for airfoil validation. For calculation of the zero lift drag, an approximation was computed in order to calculate the remaining values that were not calculated by the software: drag contribution for fuselages, nacelles and some horizontal stabilizers and fins. Different types of aircraft were selected for trial: two commercial aircraft (Boeing 747-100 and 777-300), a TF-8A research airplane (with area rule application: some additions were made to the fuselage to prevent large variations in the cross-section when the contribution of the wing is added), a Lockheed Constellation C-69 u sed as a military cargo airplane, a Boeing Stratocruiser used by the USAF with two configurations (basic and bomber), and an Aero Commander 680 Super, similar to a Cessna 162. Two airfoils (NACA2412, 0012) were also analyzed, to investigate the limitations of software designed for three-dimensional calculations. The accuracy of the results showed that the validity of the software depends on the planform of the aircraft, as well as the simulation parameters Mach number and Reynolds number. The shape of the wing caused some of the methods to have serious difficulties in converging to valid results, or increased the simulation time beyond acceptable limits. / Numera finns det olika program för beräkning av de aerodynamiska koefficienterna från en modell med vissa förenklingar som ger en snabb approximation av värdena för ett verkligt flygplan. Fyra olika program har analyserats för denna rapport: Tornado, AVL, PANAIR och en handbok baserad preliminär metod. Dessutom användes ANSYS CFX för validering av vingprofiler . Vid beräkningen av noll-lyft motståndet, en approximation användes för de återstående delarna som inte beräknas av de andra metoderna: motståndsbidraget från flygkroppar, gondoler och vissa horisontella stabilisatorer och fenor. Olika flygplaner har testats: två trafikflygplan (Boeing 747-100 och 777-300), ett TF-8A forskningsflygplan (med area regel användning: några tillägg gjordes på flygkroppen för att tvärsnitten inte har stora variationer när bidraget från vingen läggas), ett Lockheed Constellation C-69, ett Boeing Stratocruiser som används av USAF i två konfigurationer (den vanliga och bombplan), och ett Aero Commander 680 Super, som liknar ett Cessna 162. Två vingprofiler (NACA 2412, 0012) analyserades också, för att kontrollera begränsningarna av programmen avsedd för tredimensionella beräkningar. Riktigheten av resultaten visade att giltigheten av programmen beror på formen av flygplanernas vingar, samt de simulationernas parametrar: Mach nummer och Reynolds nummer. Formen på vingen orsakade några av de metoderna att ha stora svårigheter med konvergensen till giltiga resultat, eller ökat simulering tid över acceptabla gränser.
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Validation of software for the calculation ofaerodynamic coefficients : with a focus on the software package TornadoLopez Pereira, Ramon January 2010 (has links)
<p>Several programs exist today for calculating aerodynamic coefficients that with some simplificationsprovide fast approximations of the values for a real aircraft.Four different programs were analyzed for this report: Tornado, AVL, PANAIR and a handbook-typepreliminary method. In addition, ANSYS CFX was used for airfoil validation. For calculation of the zerolift drag, an approximation was computed in order to calculate the remaining values that were notcalculated by the software: drag contribution for fuselages, nacelles and some horizontal stabilizersand fins.Different types of aircraft were selected for trial: two commercial aircraft (Boeing 747-100 and 777-300), a TF-8A research airplane (with area rule application: some additions were made to the fuselageto prevent large variations in the cross-section when the contribution of the wing is added), a LockheedConstellation C-69 used as a military cargo airplane, a Boeing Stratocruiser used by the USAF withtwo configurations (basic and bomber), and an Aero Commander 680 Super, similar to a Cessna 162.Two airfoils (NACA2412, 0012) were also analyzed, to investigate the limitations of software designedfor three-dimensional calculations.The accuracy of the results showed that the validity of the software depends on the planform of theaircraft, as well as the simulation parameters Mach number and Reynolds number. The shape of thewing caused some of the methods to have serious difficulties in converging to valid results, orincreased the simulation time beyond acceptable limits.</p> / <p>Numera finns det olika program för beräkning av de aerodynamiska koefficienterna från en modellmed vissa förenklingar som ger en snabb approximation av värdena för ett verkligt flygplan.Fyra olika program har analyserats för denna rapport: Tornado, AVL, PANAIR och en handbokbaserad preliminär metod. Dessutom användes ANSYS CFX för validering av vingprofiler . Vidberäkningen av noll-lyft motståndet, en approximation användes för de återstående delarna som inteberäknas av de andra metoderna: motståndsbidraget från flygkroppar, gondoler och vissa horisontellastabilisatorer och fenor.Olika flygplaner har testats: två trafikflygplan (Boeing 747-100 och 777-300), ett TF-8Aforskningsflygplan (med area regel användning: några tillägg gjordes på flygkroppen för att tvärsnitteninte har stora variationer när bidraget från vingen läggas), ett Lockheed Constellation C-69, ett BoeingStratocruiser som används av USAF i två konfigurationer (den vanliga och bombplan), och ett AeroCommander 680 Super, som liknar ett Cessna 162. Två vingprofiler (NACA 2412, 0012) analyseradesockså, för att kontrollera begränsningarna av programmen avsedd för tredimensionella beräkningar.Riktigheten av resultaten visade att giltigheten av programmen beror på formen av flygplanernasvingar, samt de simulationernas parametrar: Mach nummer och Reynolds nummer. Formen på vingenorsakade några av de metoderna att ha stora svårigheter med konvergensen till giltiga resultat, ellerökat simulering tid över acceptabla gränser.</p>
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Validation of software for the calculation ofaerodynamic coefficients : with a focus on the software package TornadoLopez Pereira, Ramon January 2010 (has links)
Several programs exist today for calculating aerodynamic coefficients that with some simplificationsprovide fast approximations of the values for a real aircraft.Four different programs were analyzed for this report: Tornado, AVL, PANAIR and a handbook-typepreliminary method. In addition, ANSYS CFX was used for airfoil validation. For calculation of the zerolift drag, an approximation was computed in order to calculate the remaining values that were notcalculated by the software: drag contribution for fuselages, nacelles and some horizontal stabilizersand fins.Different types of aircraft were selected for trial: two commercial aircraft (Boeing 747-100 and 777-300), a TF-8A research airplane (with area rule application: some additions were made to the fuselageto prevent large variations in the cross-section when the contribution of the wing is added), a LockheedConstellation C-69 used as a military cargo airplane, a Boeing Stratocruiser used by the USAF withtwo configurations (basic and bomber), and an Aero Commander 680 Super, similar to a Cessna 162.Two airfoils (NACA2412, 0012) were also analyzed, to investigate the limitations of software designedfor three-dimensional calculations.The accuracy of the results showed that the validity of the software depends on the planform of theaircraft, as well as the simulation parameters Mach number and Reynolds number. The shape of thewing caused some of the methods to have serious difficulties in converging to valid results, orincreased the simulation time beyond acceptable limits. / Numera finns det olika program för beräkning av de aerodynamiska koefficienterna från en modellmed vissa förenklingar som ger en snabb approximation av värdena för ett verkligt flygplan.Fyra olika program har analyserats för denna rapport: Tornado, AVL, PANAIR och en handbokbaserad preliminär metod. Dessutom användes ANSYS CFX för validering av vingprofiler . Vidberäkningen av noll-lyft motståndet, en approximation användes för de återstående delarna som inteberäknas av de andra metoderna: motståndsbidraget från flygkroppar, gondoler och vissa horisontellastabilisatorer och fenor.Olika flygplaner har testats: två trafikflygplan (Boeing 747-100 och 777-300), ett TF-8Aforskningsflygplan (med area regel användning: några tillägg gjordes på flygkroppen för att tvärsnitteninte har stora variationer när bidraget från vingen läggas), ett Lockheed Constellation C-69, ett BoeingStratocruiser som används av USAF i två konfigurationer (den vanliga och bombplan), och ett AeroCommander 680 Super, som liknar ett Cessna 162. Två vingprofiler (NACA 2412, 0012) analyseradesockså, för att kontrollera begränsningarna av programmen avsedd för tredimensionella beräkningar.Riktigheten av resultaten visade att giltigheten av programmen beror på formen av flygplanernasvingar, samt de simulationernas parametrar: Mach nummer och Reynolds nummer. Formen på vingenorsakade några av de metoderna att ha stora svårigheter med konvergensen till giltiga resultat, ellerökat simulering tid över acceptabla gränser.
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Estimation of Aerodynamic Parameters in Real-Time : Implementation and Comparison of a Sequential Frequency Domain Method and a Batch MethodNyman, Lina January 2016 (has links)
The flight testing and evaluation of collected data must be efficient during intensive flight-test programs such as the ones conducted during development of new aircraft. The aim of this thesis has thus been to produce a first version of an aerodynamic derivative estimation program that is to be used during real-time flight tests. The program is to give a first estimate of the aerodynamic derivatives as well as check the quality of the data collected and thus serve as a decision support during tests. The work that has been performed includes processing of data in order to use it in computations, comparing a batch and a sequential estimation method using real-time data and programming a user interface. All computations and programming has been done in Matlab. The estimation methods that have been compared are both built on transforming data to the frequency domain using a Chirp z-transform and then estimating the aerodynamic derivatives using complex least squares with instrumental variables.The sequential frequency domain method performs estimates at a given interval while the batch method performs one estimation at the end of the maneuver. Both methods compared in this thesis produce equal results. The continuous updates of the sequential method was however found to be better suited for a real-time application than the single estimation of the batch method. The telemetric data received from the aircraft must be synchronized to a common frequency of 60 Hz. Missing samples of the data stream must be linearly interpolated and different units of measured parameters must be corrected in order to be able to perform these estimations in the real-time test environment.
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A ação do vento em silos cilíndricos de baixa relação altura/diâmetro / The wind action on cylindrical silos of low height/diameter ratioAndrade Junior, Luciano Jorge de 12 June 2002 (has links)
Os silos metálicos cilíndricos de chapa corrugada e cobertura cônica são as unidades mais utilizadas no Brasil para o armazenamento de produtos granulares. As principais ações variáveis que atuam sobre os silos são as pressões devidas aos produtos armazenados e ao vento, sendo esta ação crítica quando o silo se encontra vazio. Devido à grande eficiência estrutural da forma cilíndrica e à resistência elevada do aço, estas estruturas são leves e delgadas e, portanto, suscetíveis a perdas de estabilidade local e global e arrancamento. Com a finalidade de avaliar estes efeitos foram realizados estudos teóricos e experimentais sobre as ações do vento em silos. O trabalho foi desenvolvido com ensaios de modelos aerodinâmicos e aeroelásticos em um túnel de vento na Universidade de Cranfield, Inglaterra, com o objetivo de determinar os coeficientes aerodinâmicos no costado e na cobertura. Os resultados mostram que os valores dos coeficientes recomendados pela Norma Brasileira de vento, NBR 6123 (1990), são adequados para o costado. Para a cobertura cônica, como não são especificados pela NBR, são recomendados valores dos coeficientes aerodinâmicos determinados nos ensaios. Conclui-se também que a colocação externa das colunas é a favor da segurança e que o uso de anéis enrijecedores no costado é indicado e muito importante para a estabilidade local e global da estrutura do silo. / The steel cylindrical silos made of corrugated sheets with conical roofs are the most used units to the storage of granular materials. The main silo loads are the pressures due to the stored material and to the wind, being this action the critical one when the silo is empty. Due to the high efficiency of the cylindrical form and to the high strength of the steel, these structures are thin and light-weight and, as a consequence, susceptible to the loss of local and global stability and to the pull out of the structure. With the aim to assess these effects related to the wind loading in silos, some theoretical and experimental studies were conducted. The work was carried out with aerodynamic and aeroelastic models tested in a boundary layer wind tunnel in the University of Cranfield, England, with the objective to determine the aerodynamic coefficients of the cylinder and the conical roof. The results show that the coefficients of the Brazilian Code of wind loads, NBR 6123 (1990), are adequate to the cylinder. The coefficients to the conical roof are suggested based on our tests, considering that there are no values specified by the NBR. As well it is concluded that the outside columns is on the side of safety and it is indicated the use of wind rings attached to the cylinder, which are very important to the local and global stability of the silo structure.
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Identification des coefficients aérodynamiques d'un projectile à partir de mesures prises en vol / Identification of the aerodynamic coefficients of a projectile from flight dataDemailly, Hélène 15 December 2011 (has links)
La maîtrise du comportement en vol d’un projectile est, en partie, conditionnée par la connaissance des coefficients associés à chaque effort aérodynamique. Différents outils sont utilisés dans l’industrie, tels que les codes numériques aérodynamiques ou les essais en soufflerie, afin d’obtenir une première estimation des coefficients en phase d’avant-projet. Il est ensuite nécessaire de vérifier la valeur des coefficients et de valider le comportement du projectile en vol au moyen de tirs instrumentés. Un outil automatisé est donc proposé afin d’identifier les coefficients aérodynamiques d’un projectile à partir des mesures issues d’un vol. La technique d’identification est pensée pour être applicable à une gamme la plus large de projectiles. Elle introduit un problème d’optimisation non linéaire en dimension finie. La fonctionnelle du problème contient deux termes : un terme d’écart entre les paramètres d’état et les mesures, de sorte à s’approcher au mieux des mesures et à les relaxer, et un terme de pénalisation prenant en compte les équations de la mécanique du vol. L’outil proposé est testé, pour un projectile de type flèche, avec des données simulées ou avec des données issues de tirs. Il permet l’identification des coefficients aérodynamiques recherchés. L’algorithme est robuste face au bruit et permet également la reconstruction d’une trajectoire débruitée. / The control of the flight behaviour of a projectile partly depends on the knowledge of the coefficients associated with each aerodynamic loading. Different tools are used in the industry, such as numerical aerodynamic codes or wind tests in order to obtain a first estimate of the coefficients during the stage of pilot study. It is then necessary to verify the value of the coefficients and to validate the behaviour of the projectile thanks to scored fires. An automated tool is consequently proposed in order to identify the aerodynamic coefficients of a projectile from flight data. The identification technique is designed so as to be applicable to the widest range of projectiles. It presents a nonlinear optimization problem in finite dimension. The functional of the problem contains two terms : the first one is a gap between the state parameters and the measurements, in order to approach the measurements at best and to relax them, and the second one is a penalization term which takes the flight mechanics equations into account. The proposed tool is tested, for a Kinectic Energy projectile, with simulated data or real flight data. It enables the identification of the searched out aerodynamic coefficients. The algorithm is robust in a noisy environment and also enables the reconstruction of a denoised trajectory.
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A ação do vento em silos cilíndricos de baixa relação altura/diâmetro / The wind action on cylindrical silos of low height/diameter ratioLuciano Jorge de Andrade Junior 12 June 2002 (has links)
Os silos metálicos cilíndricos de chapa corrugada e cobertura cônica são as unidades mais utilizadas no Brasil para o armazenamento de produtos granulares. As principais ações variáveis que atuam sobre os silos são as pressões devidas aos produtos armazenados e ao vento, sendo esta ação crítica quando o silo se encontra vazio. Devido à grande eficiência estrutural da forma cilíndrica e à resistência elevada do aço, estas estruturas são leves e delgadas e, portanto, suscetíveis a perdas de estabilidade local e global e arrancamento. Com a finalidade de avaliar estes efeitos foram realizados estudos teóricos e experimentais sobre as ações do vento em silos. O trabalho foi desenvolvido com ensaios de modelos aerodinâmicos e aeroelásticos em um túnel de vento na Universidade de Cranfield, Inglaterra, com o objetivo de determinar os coeficientes aerodinâmicos no costado e na cobertura. Os resultados mostram que os valores dos coeficientes recomendados pela Norma Brasileira de vento, NBR 6123 (1990), são adequados para o costado. Para a cobertura cônica, como não são especificados pela NBR, são recomendados valores dos coeficientes aerodinâmicos determinados nos ensaios. Conclui-se também que a colocação externa das colunas é a favor da segurança e que o uso de anéis enrijecedores no costado é indicado e muito importante para a estabilidade local e global da estrutura do silo. / The steel cylindrical silos made of corrugated sheets with conical roofs are the most used units to the storage of granular materials. The main silo loads are the pressures due to the stored material and to the wind, being this action the critical one when the silo is empty. Due to the high efficiency of the cylindrical form and to the high strength of the steel, these structures are thin and light-weight and, as a consequence, susceptible to the loss of local and global stability and to the pull out of the structure. With the aim to assess these effects related to the wind loading in silos, some theoretical and experimental studies were conducted. The work was carried out with aerodynamic and aeroelastic models tested in a boundary layer wind tunnel in the University of Cranfield, England, with the objective to determine the aerodynamic coefficients of the cylinder and the conical roof. The results show that the coefficients of the Brazilian Code of wind loads, NBR 6123 (1990), are adequate to the cylinder. The coefficients to the conical roof are suggested based on our tests, considering that there are no values specified by the NBR. As well it is concluded that the outside columns is on the side of safety and it is indicated the use of wind rings attached to the cylinder, which are very important to the local and global stability of the silo structure.
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Flight and Stability of a Laser Inertial Fusion Energy Target in the Drift Region Between Injection and the Reaction Chamber with Computational Fluid DynamicsMitori, Tiffany Leilani 01 March 2014 (has links) (PDF)
A Laser Inertial Fusion Energy (LIFE) target’s flight through a low Reynolds number and high Mach number regime was analyzed with computational fluid dynamics software. This regime consisted of xenon gas at 1,050 K and approximately 6,670 Pa. Simulations with similar flow conditions were performed over a sphere and compared with experimental data and published correlations for validation purposes. Transient considerations of the developing flow around the target were explored. Simulations of the target at different velocities were used to determine correlations for the drag coefficient and Nusselt number as functions of the Reynolds number. Simulations with different target angles of attack were used to determine the aerodynamic coefficients of drag, lift, Magnus moment, and overturning moment as well as target stability. The drag force, lift force, and overturning moment changed minimally with spin. Above an angle of attack of 15°, the overturning moment would be destabilizing. At angles of attack less than 15°, the overturning moment would tend to decrease the target’s angle of attack, indicating the lack of a need for spin for stability at these small angles. This stabilizing moment would cause the target to move in a mildly damped oscillation about the axis parallel to the free-stream velocity vector through the target’s center of gravity.
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Aerodynamic Validation of Emerging Projectile ConfigurationsSor, Wei Lun 01 November 2012
Approved for public release; distribution is unlimited. / Ever-increasing demands for accuracy and range in modern warfare have expedited the optimization of projectile design. The crux of projectile design lies in the understanding of its aerodynamic properties early in the design phase. This research first investigated the aerodynamic properties of a standard M549, 155mm projectile. The transonic speed region was the focus of the research as significant aerodynamic variation occurs within this particular region. Aerodynamic data from wind tunnel and range testing was benchmarked against modern aerodynamic prediction programs like ANSYS CFX and Aero-Prediction 09 (AP09). Next, a comparison was made between two types of angle of attack generation methods in ANSYS CFX. The research then focused on controlled tilting of the projectile’s nose to investigate the resulting aerodynamic effects. ANSYS CFX was found to provide better agreement with the experimental data than AP09.
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