Relevant bibliographies by topics / Equation de von Kármán

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Academic literature on the topic 'Equation de von Kármán'

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Published: 4 June 2021
Last updated: 8 February 2022

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Journal articles on the topic "Equation de von Kármán"

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CIARLET, PHILIPPE G., LILIANA GRATIE, and SRINIVASAN KESAVAN. "ON THE GENERALIZED VON KÁRMÁN EQUATIONS AND THEIR APPROXIMATION." Mathematical Models and Methods in Applied Sciences 17, no. 04 (April 2007): 617–33. http://dx.doi.org/10.1142/s0218202507002042.

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We consider here the "generalized von Kármán equations", which constitute a mathematical model for a nonlinearly elastic plate subjected to boundary conditions "of von Kármán type" only on a portion of its lateral face, the remaining portion being free. As already shown elsewhere, solving these equations amounts to solving a "cubic" operator equation, which generalizes an equation introduced by Berger and Fife. Two noticeable features of this equation, which are not encountered in the "classical" von Kármán equations are the lack of strict positivity of its cubic part and the lack of an associated functional. We establish here the convergence of a conforming finite element approximation to these equations. The proof relies in particular on a compactness method due to J. L. Lions and on Brouwer's fixed point theorem. This convergence proof provides in addition an existence proof for the original problem.
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Ciarlet, Philippe G., and Liliana Gratie. "On the Existence of Solutions to the Generalized Marguerre-von Kármán Equations." Mathematics and Mechanics of Solids 11, no. 1 (February 2006): 83–100. http://dx.doi.org/10.1177/1081286505046480.

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Using techniques from asymptotic analysis, the second author has recently identified equations that generalize the classical Marguerre-von Kármán equations for a nonlinearly elastic shallow shell by allowing more realistic boundary conditions, which may change their type along the lateral face of the shell. We first reduce these more general equations to a single “cubic” operator equation, whose sole unknown is the vertical displacement of the shell. This equation generalizes a cubic operator equation introduced by M. S. Berger and P. Fife for analyzing the von Kármán equations for a nonlinearly elastic plate. We then establish the existence of a solution to this operator equation by means of a compactness method due to J. L. Lions.
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PARK, JONG YEOUL, SUN HYE PARK, and YONG HAN KANG. "BILINEAR OPTIMAL CONTROL OF THE VELOCITY TERM IN A VON KÁRMÁN PLATE EQUATION." ANZIAM Journal 54, no. 4 (April 2013): 291–305. http://dx.doi.org/10.1017/s1446181113000205.

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AbstractWe consider a bilinear optimal control problem for a von Kármán plate equation. The control is a function of the spatial variables and acts as a multiplier of the velocity term. We first state the existence of solutions for the von Kármán equation and then derive optimality conditions for a given objective functional. Finally, we show the uniqueness of the optimal control.
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Ciarlet, Philippe G., and Liliana Gratie. "Generalized von Kármán equations." Journal de Mathématiques Pures et Appliquées 80, no. 3 (April 2001): 263–79. http://dx.doi.org/10.1016/s0021-7824(00)01198-3.

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Fattorusso, Luisa, and Antonio Tarsia. "Von Kármán equations inLpspaces." Applicable Analysis 92, no. 11 (November 2013): 2375–91. http://dx.doi.org/10.1080/00036811.2012.738362.

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Wang, Jiujiang, Xin Liu, Yuanyu Yu, Yao Li, Ching-Hsiang Cheng, Shuang Zhang, Peng-Un Mak, Mang-I. Vai, and Sio-Hang Pun. "A Review on Analytical Modeling for Collapse Mode Capacitive Micromachined Ultrasonic Transducer of the Collapse Voltage and the Static Membrane Deflections." Micromachines 12, no. 6 (June 18, 2021): 714. http://dx.doi.org/10.3390/mi12060714.

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Analytical modeling of capacitive micromachined ultrasonic transducer (CMUT) is one of the commonly used modeling methods and has the advantages of intuitive understanding of the physics of CMUTs and convergent when modeling of collapse mode CMUT. This review article summarizes analytical modeling of the collapse voltage and shows that the collapse voltage of a CMUT correlates with the effective gap height and the electrode area. There are analytical expressions for the collapse voltage. Modeling of the membrane deflections are characterized by governing equations from Timoshenko, von Kármán equations and the 2D plate equation, and solved by various methods such as Galerkin’s method and perturbation method. Analytical expressions from Timoshenko’s equation can be used for small deflections, while analytical expression from von Kármán equations can be used for both small and large deflections.
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Hornung, Peter. "A remark on constrained von Kármán theories." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, no. 2170 (October 8, 2014): 20140346. http://dx.doi.org/10.1098/rspa.2014.0346.

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Wang, Yongda. "An evolution von Kármán equation modeling suspension bridges." Nonlinear Analysis 169 (April 2018): 59–78. http://dx.doi.org/10.1016/j.na.2017.12.002.

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Cibula, Július. "Von Kármán equations. III. Solvability of the von Kármán equations with conditions for geometry of the boundary of the domain." Applications of Mathematics 36, no. 5 (1991): 368–79. http://dx.doi.org/10.21136/am.1991.104473.

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Bock, I. "On Nonstationary von Kármán Equations." ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik 76, no. 10 (1996): 559–71. http://dx.doi.org/10.1002/zamm.19960761006.

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Dissertations / Theses on the topic "Equation de von Kármán"

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El, Doussouki Ayman. "Contribution à l'étude des équations de Föppl von Kármán : applications aux phénomènes de cloquage." Amiens, 2012. http://www.theses.fr/2012AMIE0117.

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Dans cette thèse nous allons traiter deux types de contraintes résiduelles : thermique et mécanique. Le premier modèle s'obtient par développement asymptotique (Chapitre 2). Le deuxième modèle s'obtient en utilisant les hypothèses de Landau Lifschitz (Chapitre 5). Dans le deuxième chapitre, nous établissons les équations de flambage d'une plaque élastique mince. Notre point de vue est formel, et consiste à appliquer la méthode des développements asymptotiques à l'énergie initiale posée sur [. . . ] représentant la plaque, pour obtenir un problème limite écrit sur son plan moyen. Ce qui nous permet d'utiliser le modèle de Kirchhoff-Love pour le déplacement limite en [. . . ], qui est défini dans le plan moyen. Alors on obtient d'une part l'obtention des équations Euler-Lagrange correspondant à l'énergie en fonction de [. . . ] et d'autre part l'obtention des équations de Fopple von Kármán, qui sont caractérisées par leurs non linéarité et par leurs aspects bidimensionnels (dans le sens que les inconnues s'expriment en fonction de deux variables qui sont les coordonnées des points du plan moyen). Dans le troisième chapitre, on montre l'existence d'un minimiseur de l'énergie et en conséquence, l'existence de solution du système FvK. Par régularités elliptiques, on montre d'une part, que le minimiseur est dans [. . . ] et d’autre part, la solution du système FvK est dans [. . . ]. Dans le quatrième chapitre, nous avons ajouté un terme source au second membre et on montre l’existence de solution par une estimation à priori. En plus, on a effectué quelques simulations numériques des équations de FvK avec des conditions aux bords convenables. Le but de ce chapitre est de voir la formation de différents types de cloques (rectiligne, circulaire,. . . ). Pour cela, on met en œuvre une méthode d'éléments finis. Le cinquième chapitre est consacré à l'obtention des équations FvK suivant l'hypothèse de Landau et Lifschitz. Cette obtention a été faite en coordonnées cylindriques, puis on en obtient les équations radiales de FvK. Dans le sixième chapitre on montre la non existence des solutions radiales non triviales dans le cas de compression et sous les conditions aux bords convenable. Cela a été fait en étudiant les propriétés de la composante normale de la contrainte
In this thesis we will treat two types of residual stresses : thermal and mechanical. The first model is obtained by asymptotic expansion (chapter 2). The second model is obtained by using the hypothesis of Landau Lifschitz (chapter 5). In the second chapter, we establish the equation of buckling of a thin elastic plate. We obtain a derivation of the equations from the Euler-Lagrange corresponding to the energy as a function of [. . . ] and secondly the derivation of equations Fopple von Kármán, which are characterized by their non-linear two-dimensional appearance (in the sense that the unknows are expressed function of two variables that are the coordinates of the mean plane). In the third chapter, we show the existence of a minimizer of the energy and accordingly, the existence of solution of the system FvK. By elliptic regularity, we show first, that the minimizer is in [. . . ] and on the other hand, the solution of FvK system is [. . . ]. In the fourth chapter, we added a source term to the second member and we show the existence of solution, by a priori estimation. In addition, we have performed some numerical simulations of FvK equations with suitable boundary conditions. The fifth chapter is devoted to the derivation of the equations following FvK Landau's hypothesis. This derivation was made in cylindrical coordinates, then we obtain the equations of radial FvK. In the sixth chapter we prove the nonexistence of non trivial radial solutions in the case of compression and under suitable boundary conditions
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Legrand, Mathilde. "Etude mathématique de modèles de couches visqueuses pour des écoulements naturels." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2047/document.

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Le système de Saint Venant est répandu pour modéliser des fluides dont la hauteur est inférieure au domaine d'écoulement. Son écriture nécessite des hypothèses sur le profil de vitesse pour connaître le flux de la quantité de mouvement ainsi que le cisaillement sur le fond. Dans cette thèse, nous nous sommes intéressés à un couplage entre un fluide parfait et une couche visqueuse dans l'esprit des couches limites interactives (IBL) introduites en aéronautique. Cette interaction nous permet de proposer un terme de friction en adéquation avec les attentes physiques au regard de la position du maximum local. Une part importante de cette thèse est donc consacrée à la compréhension de la couche visqueuse dans laquelle la recherche du profil de vitesse est cantonnée. Cette étude se décompose en l'écriture des équations de Prandtl puis en l'établissement de l'équation de von Kármán. Cette dernière met en jeu les quantités nécessaires à la définition du flux recherché et est donc un élément clé de la fermeture du système. Des résultats numériques viennent illustrer le modèle obtenu par le couplage entre le fluide parfait et la couche visqueuse. Le dernier chapitre expose deux formulations alternatives obtenues d'un point de vue d'un écoulement d'un fluide parfait dont les conditions sur les bords du domaine sont modifiées, soit par une condition de transpiration définie sur le fond, soit par une modification du domaine enlien avec une topographie apparente
Shallow Water system is widely used for flows when the depth is smaller than the longitudinal scale. The establishment needs some hypothesis on the velocity profile in order to describe the moment flux and the shear stress on ground. In this thesis, we present a two layer decomposition of the fluid between an ideal fluid and a viscous layer in the spirit of the Interactive Boundary Layer (IBL) introduced in aeronautics. This interaction leads to obtain in our equations a friction term which fits with the physical expectations for the local maximum. So a major part of this work is interested in the comprehension of the viscous layer where the velocity profile is confined. The study is based on the writing of Prandtl equations then the establishment of the von Kármán equation. The last one contains the necessary quantities for a definition of the researched flux. Also this equation is essential for a closure of the system. Some numerical results illustrate the proposed model with the association of ideal fluid ans viscous layer. A last chapter presents two alternatives formulations of the model based on an ideal fluid with modified boundary conditions. The first one keeps the same domain but has a transpiration boundary
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Souza, Tiago da Silva. "Geração de vórtices de Von Kármán com modelagem em CFD." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-30032017-113355/.

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Assim como um peixe pode aproveitar a energia dos vórtices formados por uma rocha em uma corredeira para economizar energia e produzir impulso, este trabalho tem por objetivo mostrar que os vórtices de von Kármán ou esteira de vórtices, desprendidos de um corpo cilíndrico colocado em um escoamento contínuo, com uma placa de um determinado comprimento, posicionada atrás desse corpo cilíndrico e com movimentos livres na horizontal, pode vibrar e produzir movimentos rotacionais, e por fim, uma frequência, com o objetivo de se aproveitar esse movimento para geração de energia. Para tanto, utilizou-se software CFD (Computational Fluid Dynamic), para observar e quantificar os movimentos produzidos pela placa. Observou-se também, entre três comprimentos de placa, com três velocidades diferentes, três números de Reynolds diferentes e com escoamentos laminar e turbulento, como as placas se comportam e qual delas produz movimento com maior frequência. Buscou-se também verificar a eficiência do movimento para números de Strouhal menores e iguais a 0,21.
Just as a fish can harness the energy of the vortices formed by a rock in the rapids to save energy and produce impulse this paper aims to show that the von Kármán vortex or wake vortex, detached from a cylindrical body placed in a flow continuous with a plate of a certain length, positioned behind this cylindrical body and freely moving horizontally, may vibrate and produce rotational movements, and finally, a frequency, in order to take advantage of this movement to generate power. Therefore, we used CFD software (Computational Fluid Dynamic), to observe and quantify the movements produced by the board. It was also observed between three plate lengths with three different velocities, three different Reynolds numbers and laminar and turbulent flow as the plates behave and which one produces motion with higher frequency. It sought to verify the efficiency of movement to lower Strouhal numbers and equal to 0.21.
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Saint-Michel, Brice. "L'écoulement de von Kármán comme paradigme de la physique statistique hors de l'équilibre." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2013. http://tel.archives-ouvertes.fr/tel-00911544.

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Cette thèse tente d'effectuer une approche de physique statistique (à l'équilibre et hors équilibre) d'un écoulement pleinement turbulent de von Kármán produit par la contra-rotation de deux turbines dans un cylindre rempli de fluide. Dans une première partie, les résultats expérimentaux obtenus en commande en vitesse sont complétés par des observations par PIV, puis étudiés dans le cadre de la mécanique statistique : la divergence de susceptibilité qui est notamment observée est étudiée à la manière d'un modèle d'Ising-Champ moyen, dans lequel les corrélations spatiales de l'écoulement et le théorème fluctuation-dissipation sont examinés. En second lieu, les résultats de commande en couple sont complétés : l'existence de réponses différentielles négatives dans l'écoulement autorise une analogie avec certains dipôles électriques et fluides complexes. Nous interprétons ces résultats comme une forme d'inéquivalence d'ensemble, typique des systèmes possédant des interactions à longue portée. Les temps d'échappement des régimes multi-stables sont également étudiés comme un simple problème de puits de potentiel de Kramers, révélant une dynamique globale à petit nombre de degrés de liberté. Finalement, des résultats préliminaires de l'expérience SHREK effectuées dans l'hélium à très basse température sont présentés. Les couples mécaniques exercés sur les turbines sont similaires dans le cas du fluide normal et du superfluide. Les nombres de Reynolds accessibles dans l'expérience permettent en outre une étude plus complète du cycle d'hystérésis en fonction du nombre de Reynolds.
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Boronski, Piotr. "Méthode des potentiels poloïdal-toroïdal appliquée à l'écoulement de von Kármán en cylindre fini." Phd thesis, Ecole Polytechnique X, 2005. http://tel.archives-ouvertes.fr/tel-00162594.

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Ce travail est motivé par l'effort international actuel de créer expérimentalement une dynamo fluide auto-entretenue. L'effet dynamo, dont l'existence a été prevu par Larmor au début du XXème siècle, est considéré comme étant responsable de la production du champ matnétique terrestre et d'autres objets célestes par l'intermédiaire de l'écoulement d'un fluide conducteur. Afin d'étudier numériquement l'écoulement de von Kármán, qui modélise la configuration d'une expérience dynamo mise en place à Cadarache, nous avons développé une approche numérique originale permettant la résolution des équations magnétohydrodynamiques dans une géométrie dylindrique en formulation potentielle. La décomposition en potentiels poloïdal et toroïdal a été utilisée pour garantir la nature solénoïdale des champs de vitesse et magnétique. Nous utilisons la technique de la matrice d'influence pour satisfaire aux conditions aux limites et aux conditions de continuité du champ magnétique à la paroi du cylindre. La grande puissance de calcul, résultant de la parallélisation MPI du code, a presmis de l'appliquer deux problèmes concernant la turbulence dans la géométrie cylindrique : la turbulence axisymétrique et une bifurcation entre états turbulents.
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Titon, Jean. "Forçages, transfert d'énergie et structures cohérentes dans un écoulement turbulent de Von Kármán contrarotatif." Le Havre, 2003. http://www.theses.fr/2003LEHA0003.

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L'influence des filaments de basse pression sur les fluctuations de la puissance globale injectée dans un écoulement turbulent de Von Kármán contrarotatif est étudiée. La stratégie expérimentale consiste à piloter les servomoteurs actionnant les batteurs à vitesse angulaire constante ou à couple constant. Dans le premier cas, la régulation face aux forces de traînée turbulente se fait sur les couples délivrés. Dans le second, il s'agit d'un contrôle naturel de l'écoulement sur les dispositifs de forçage. On met ainsi en évidence l'influence du mode de forçage sur les fluctuations de la puissance injectée. L'analyse des mesures locales (vitesse et pression) montre que les propriétés des petites échelles des écoulements ainsi produits sont les mêmes. L'extraction de la moyenne de phase de la puissance injectée conditionnée par la détection d'un filament aboutit au scénario du transfert d'énergie associé. Un modèle expliquant les différences entre les deux modes d'injection est proposé
The influence of low pressure filaments on the fluctuations of the global power injected in a Von Kármán turbulent flow is studied. The experimental strategy consists in operating the servomotors that drive the counter-rotating stirrers either at constant angular velocity or with a constant torque. In the first case, the regulating system responds to the turbulent drag forces by correcting the torque delivered. In the second case, there is a natural control of the flow on the forcing devices. The influence of the forcing modes on the fluctuations of the power injected is outlined by this method whereas the analysis of local quantities (velocity and pressure) show no differences in the small scale properties of the turbulent flows hence produced. Extracting the phase average of the injected power conditioned by the presence of a filament leads to the scenario of the corresponding energy transfer process. A model explaining the differences between the two injection modes is suggested
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Souza, Pammella Queiroz de. "Estabilização da Equação de Berger-Timoshenko como Limite Singular da Estabilização Uniforme do Sistema de Von-Kármán para Vigas." Universidade Federal da Paraí­ba, 2012. http://tede.biblioteca.ufpb.br:8080/handle/tede/7406.

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We consider a dynamical one-dimensional nonlinear Von Kármán model for beams depending on the parameter " > 0 and we study their asymptotic behavior for t large, when " ! 0. Introducing appropriate damping mechanisms we show that the energy of solutions of the corresponding damped models decay exponential uniform with respect to the parameter ". In order for this to be true the damping mechanism has to have the appropriate scale with respect to ". In the limit as " ! 0 we obtain damped Berger- Timoshenko beam model for which the energy tends exponentially to zero. This is done both in the case of internal and boundary damping .
Consideramos a dinâmica unidimensional não linear do modelo de Von Kármán para vigas dependendo de um parâmetro " > 0, e estudamos o seu comportamento assintótico para t grande, quando " ! 0. Introduzindo mecanismos adequados de amortecimento, mostramos que a energia de soluções do correspondente modelo amortecido possui decaimento exponencial uniforme com respeito ao parâmetro ". Afim de que seja verdadeiro, o mecanismo de amortecimento tem que ter a escala apropriada em relação a ". No limite, quando " ! 0 obtemos o modelo de Berger-Timoshenko para viga amortecida, bem como quando a energia tende exponencialmente para zero. Isso é feito tanto no caso de amortecimento interno e na fronteira.
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Hallgren, Christoffer. "Virvelgator i atmosfären." Thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-155753.

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De virvelgator som bildas i atmosfären bakom höga berg på öar påminner till utseendet starkt om de periodiska flöden som uppstår vid strömning kring en cirkulär cylinder. Friktionen mellan fluiden och cylinderns yta gör att det bildas en vak nedströms cylindern. Periodisk virvelspridning där von Kármán-virvlar sänds ut kan uppstå. Utifrån Reynolds tal går det att karaktärisera strömningen och med hjälp av en numerisk modell kan tillstånden simuleras. Saknas en turbulensmodell i algoritmen blir resultaten för höga Reynolds tal felaktiga. De atmosfäriska virvelgatorna uppstår dock inte på grund av friktion. Istället krävs blockering av luftmassor och variationer i densitet för att virvlarna ska utvecklas. För att dra slutsatser om de atmosfäriska virvelgatorna har 11 satellitbilder med virvelgator analyserats. Sambandet λ = 3.9b-5.3 (förklaringsgrad r2 = 0.91) hittades mellan virvelgatans våglängd λ och bredden b på ön. Kvoten λ/b beräknades till medelvärdet 4.33 vilket är jämförbart med resultat från en liknande studie.
The visual appearance of the atmospheric vortex street behind a high mountain on an island is very similar to the periodic pattern caused by the flow past a circular cylinder. The friction between the fluid and the surface of the cylinder creates a wake downstream of the cylinder and periodic von Kármán vortex shedding occurs. The flow may be characterized by means of the Reynolds number and using a numerical model the different states can be simulated. If the algorithm lacks a turbulence model, the results for high Reynolds numbers will be wrong. The atmospheric vortex streets do not, however, arise due to friction. Instead, blocking of air masses and density variations are needed for the vortices to develop. To be able to draw conclusions about atmospheric vortex streets 11 satellite images showing the vortex streets have been analyzed. The relation λ = 3.9b-5.3 (coefficient of determination r2 = 0.91) was found, where λ is the wavelength of the vortex street and b the width of the island. The mean value of the ratio λ/b is 4.33 which is comparable with results from a similar study.
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Salah, Nebya. "Développement de l'holographie numérique : application à la trajectographie 3D de particules dans une allée de Bénard-von Kármán." Rouen, 2009. http://www.theses.fr/2009ROUES040.

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Cette étude concerne le développement de l'holographie numérique dans l'axe pour l'application au transport des particules dans les écoulements laminaires ou turbulents. Dans le montage utilisé, une diode laser modulée éclaire un volume de fluide en mouvement ensemencé avec des particules. Les interférences créées entre la lumière diffractée par ces objets et le faisceau collimaté sont enregistrées à l'aide d’une caméra. La reconstruction numérique de l'hologramme est ensuite réalisée par un algorithme basé sur la transformée en ondelette. En illuminant le champ d'écoulement au moyen d'impulsions laser de durée et de période ajustables, on peut avoir accès aux positions 3D des gouttelettes qui l'ensemencent. Cette technique permet ainsi d'obtenir des informations Lagrangiennes dont les imprécisions de mesures restent inconnues. Dans le but d'estimer cette imprécision et de montrer les potentialités et les limites de cette technique, ce montage optique a été implanté sur une allée de Bénard-von Kármán dans laquelle des gouttelettes d'eau ont été injectées en amont. Les trajectoires obtenues à partir des enregistrements holographiques ont été localisées dans l'écoulement et la vitesse de chaque gouttelette a pu être comparée à la vitesse du fluide qui l'entoure (connue par PIV). L'analyse de ces résultats montre que l'incertitude de localisation dans la direction du faisceau est de l'ordre de 80µm. Malgré cette incertitude, on observe que les particules ne suivent pas parfaitement l'écoulement et sont influencées différemment par les diverses zones du sillage. La vitesse de chute de ces gouttelettes et leur nombre de Stokes estimé à 0,08-0,2 peuvent expliquer ce comportement
This study deals with the development of digital in-line holography for the application to particles behavior in laminar or turbulent flows. In the set-up used, a modulated laser diode enlights a volume of moving fluid seeded by particles. Interferences created by the light diffracted by particles and the collimated beam is recorded by a CCD sensor. The numerical reconstruction is then realized by an algorithm based on wavelets transform. As the flow is enlighten by laser pulses of length and period adjustable, 3D positions of the droplets seeding the flow can be determined. This technique permits obtaining Lagrangian information but their accuracy is still unknown. In order to evaluate this accuracy and to show possibilities and limits of this technique, this optical device has been set-up on a Bénard-von Kármán flow seeded by water droplets. Trajectories obtained from holographic recordings were localized in the flow and particle velocities can be compared to the flow velocity around them (known by PIV). Analyses of these results show that localization uncertainties in the laser beam direction are about 80µm. In spite of this uncertainty, one can observe that droplets do not perfectly follow the flow and are influenced differently by the various zones of the wake. Droplets falling velocities and their Stokes number assessed to 0. 08-0. 2 can explain this behavior
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Lundin, Lukas. "Tip vortex cavitation and diffused vorticity of propeller profiles: a modelling approach : Investigation of an implemented TVI model, and implementation and investigation of a DVH model." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-65102.

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To predict fluid properties and interactions is an important task for the industry. It is plagued, however, by being close to impossible to predict analytically. Hence, it is customary to turn to numerical solutions. This in itself comes with many different methods and approaches suitable for different needs. This work focuses on two methods: Tip Vortex Index (TVI) and Diffused Vortex Hydrodynamics (DVH). TVI is a method to predict when a marine propeller will experience cavitation of tip vortices and is based on calculations from a Boundary Element Method (BEM). DVH is a particle method for simulating the circulation of a fluid in two dimensions and three dimensions. The aim is to investigate an implemented TVI model based on MPUF-3A for different marine propeller series, with different sub-designs for a total of 28 unique propellers, and implement the DVH method and test it for 3 different bodies. The results of this thesis show that the implemented TVI model is non-functional for the 28 different propellers, but the DVH method is successfully implemented and able to handle 2 different bodies.
Att förutspå fluid egenskaper och interaktioner är en viktig uppgift för industrin. Det plågas dock av att vara näst intil omöjligt att förutspå analytiskt. Det är därför vanligt att vända sig till numeriska lösningar. Detta kommer i sig med många olika metoder och tillvägagångssätt som passar olika behov. Detta arbete fokuserar på två metoder: Tip Vortex Index (TVI) och Diffused Vortex Hydrodynamics (DVH). TVI är en metod för att förutsäga när en marin propeller kommer att uppleva kavitation av spetsvirvlar och baseras på beräkningar från en Boundary Element Method (BEM). DVH är en partikelmetod för att simulera cirkulationen i fluid i två dimensioner och tre dimensioner. Syftet är att undersöka en implementerad TVI-modell baserad på MPUF-3A för olika marina propellerserier, med olika underdesigner, för totalt 28 unika propellrar, och implementera DVH-metoden och testa den för 3 olika kroppar. Resultaten av denna avhandling visar att den implementerade TVI-modellen är icke-funktionell för de 28 olika propellrarna, men DVH-metoden är framgångsrikt implementerad och kan hantera 2 olika kroppar
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Books on the topic "Equation de von Kármán"

1

Nickelsen, Kärin, Alessandra Hool, and Gerd Graßhoff. Theodore von Kármán. Basel: Birkhäuser Basel, 2004. http://dx.doi.org/10.1007/978-3-0348-7957-6.

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Reister, Heinrich. Numerische Simulation der Wechselwirkung von Druckwellen mit laminaren und turbulenten Grenzschichten. Koln: DFVLR, 1987.

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Programme zur Erfassung von Landschaftsdaten, eine Bodenerosionsgleichung und ein Modell der Kaltluftentstehung =: Programmes for the collection of landdscape data, a soil erosion equation and a model showing how cold air arises. Heidelberg: Im Selbstverlag des Geographischen Institutes der Universität Heidelberg, 1986.

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Steven, Rosenberg, and Clara L. Aldana. Analysis, geometry, and quantum field theory: International conference in honor of Steve Rosenberg's 60th birthday, September 26-30, 2011, Potsdam University, Potsdam, Germany. Providence, Rhode Island: American Mathematical Society, 2012.

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Von Karman Evolution Equations Wellposedness And Long Time Dynamics. Springer, 2010.

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Escudier, Marcel. Laminar boundary layers. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198719878.003.0017.

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This chapter starts by introducing the concept of a boundary layer and the associated boundary-layer approximations. The laminar boundary-layer equations are then derived from the Navier-Stokes equations. The assumption of velocity-profile similarity is shown to reduce the partial differential boundary-layer equations to ordinary differential equations. The results of numerical solutions to these equations are discussed: Blasius’ equation, for zero-pressure gradient, and the Falkner-Skan equation for wedge flows. Von Kármán’s momentum-integral equation is derived and used to obtain useful results for the zero-pressure-gradient boundary layer. Pohlhausen’s quartic-profile method is then discussed, followed by the approximate method of Thwaites. The chapter concludes with a qualitative account of the way in which aerodynamic lift is generated.
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Theodore von Kármán: Flugzeuge für die Welt und eine Stiftung für Bern. Basel: Birkhäuser Basel, 2004.

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Air University (U.S.). Press, ed. Architects of American air supremacy: Gen. Hap Arnold and Dr. Theodore von Kármán. Maxwell Air Force Base, Ala: Air University Press, 1997.

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C, Turner James, and Institute for Computer Applications in Science and Engineering., eds. Finite element approximation of an optimal control problem for the Von Karman equations. Hampton, Va: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1994.

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C, Turner James, and Institute for Computer Applications in Science and Engineering., eds. Finite element approximation of an optimal control problem for the Von Karman equations. Hampton, Va: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1994.

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Book chapters on the topic "Equation de von Kármán"

1

Zeidler, Eberhard. "Pseudomonotone Operators, Bifurcation, and the von Kármán Plate Equations." In Nonlinear Functional Analysis and its Applications, 322–47. New York, NY: Springer New York, 1988. http://dx.doi.org/10.1007/978-1-4612-4566-7_9.

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Gazzola, Filippo, and Yongda Wang. "Modeling suspension bridges through the von Kármán quasilinear plate equations." In Contributions to Nonlinear Elliptic Equations and Systems, 269–97. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-19902-3_18.

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Bock, Igor. "On Hyperbolic Integro-differential von Kármán Equations for Viscoelastic Plates." In Hyperbolic Problems: Theory, Numerics, Applications, 87–96. Basel: Birkhäuser Basel, 1999. http://dx.doi.org/10.1007/978-3-0348-8720-5_10.

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Ghezal, A., and D. A. Chacha. "Convergence of Finite Element Approximations for Generalized Marguerre–von Kármán Equations." In Springer Proceedings in Mathematics & Statistics, 97–106. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06923-4_9.

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Lasiecka, Irena. "Asymptotic Behavior and Attractors for Nonlinear von Kármán Plate Equations with Boundary Dissipation." In Control and Optimal Design of Distributed Parameter Systems, 171–93. New York, NY: Springer New York, 1995. http://dx.doi.org/10.1007/978-1-4613-8460-1_8.

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Altenbach, Holm, and Otto T. Bruhns. "Kármán, Theodore von." In Encyclopedia of Continuum Mechanics, 1387–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 2020. http://dx.doi.org/10.1007/978-3-662-55771-6_41.

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Antman, Stuart S. "Theodore von Kármán." In Bolyai Society Mathematical Studies, 373–82. Berlin, Heidelberg: Springer Berlin Heidelberg, 2006. http://dx.doi.org/10.1007/978-3-540-30721-1_11.

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Altenbach, Holm, and Otto T. Bruhns. "Kármán, Theodore von." In Encyclopedia of Continuum Mechanics, 1–4. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-662-53605-6_41-1.

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Nickelsen, Kärin, Alessandra Hool, and Gerd Graßhoff. "Einleitung." In Theodore von Kármán, 13–15. Basel: Birkhäuser Basel, 2004. http://dx.doi.org/10.1007/978-3-0348-7957-6_1.

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Nickelsen, Kärin, Alessandra Hool, and Gerd Graßhoff. "Beginn Einer Karriere." In Theodore von Kármán, 17–55. Basel: Birkhäuser Basel, 2004. http://dx.doi.org/10.1007/978-3-0348-7957-6_2.

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Conference papers on the topic "Equation de von Kármán"

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Wang, Jiujiang, Yuanyu Yu, Sio Hang Pun, Peng Un Mak, U. Kin Che, Ching-Hsiang Cheng, and Mang I. Vai. "Analytical model with lateral force for conventional CMUT membranes under large deflection using Von Kármán equations." In 2016 IEEE International Ultrasonics Symposium (IUS). IEEE, 2016. http://dx.doi.org/10.1109/ultsym.2016.7728442.

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Kiani, Yasser, and Mohammad Reza Eslami. "Large Amplitude Thremally Induced Vibration of Circular FGM Plate." In ASME 2014 12th Biennial Conference on Engineering Systems Design and Analysis. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/esda2014-20406.

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Vibration of a solid circular plate subjected to rapid surface heating is analyzed in this research. Properties of the plate are all temperature and position dependent. Plate is modeled using the first order shear deformation theory. To account for the large deformations, the von Kármán type of geometrical non-linearity is taken into account. Plate is subjected to surface heating at both top and bottom surfaces. Time dependent one-dimensional heat conduction equation is solved via an iterative finite difference scheme and thermal force and thermal moment resultants are evaluated at each time step. Non-linear motion equations of the plate are established with the aid of Hamilton’s principle and the generalized Ritz method. Solution of such equations is obtained employing a hybrid Newton-Raphson-Newmark method. It is shown that thermally induced vibrations exist for the sufficiently thin FGM plate.
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Ghayesh, Mergen H., and Marco Amabili. "Nonlinear Dynamics of Axially Moving Plates With Rotational Springs." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65492.

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In this paper, the in-plane and out-of-plane nonlinear dynamics of an axially moving plate with distributed rotational springs at boundaries is examined numerically. The Von Kármán plate theory along with the Kirchhoff’s hypothesis are employed to construct the kinetic and potential energies of the system. The Lagrange equation is used so as to obtain the equations of motion which are in the form of a set of second-order nonlinear ordinary differential equations. This set is recast into a set of first-order nonlinear ordinary differential equations with coupled terms. Gear’s backward-differentiation-formula is employed to integrate this set of equations numerically, yielding the generalized coordinates of the system as a function of time. The bifurcation diagrams of Poincaré maps are then constructed by sectioning these time histories in every period of the external excitation force. The results are shown in the form of time histories, phase-plane portraits, and Poincaré sections. The effect of the stiffness of the rotational springs on the global dynamics of the system is also investigated.
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Jallouli, Aymen, Najib Kacem, Fehmi Najar, and Joseph Lardies. "Effects of Squeeze Film and Initial Deflection on the Resonance Frequencies and Modal Damping of Circular Microplates." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85993.

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We investigate the effects of squeeze air film and initial deflection on the resonance frequencies and modal damping of capacitive circular microplates. The equation of motion of a circular microplate, which are derived from the von kármán plate theory, coupled with the Reynolds equation are discretized using the Differential Quadrature Method (DQM). The eigenvalues and eigenvectors of the multiphysical problem are determined by perturbing the system of equations around a static solution. Therefore, the resonance frequencies, modal damping coefficients and mode shapes of the plate and the fluid can be determined. The advantage of using DQM is that the solution of the system can be obtained with only few grid points. The obtained numerical results are compared with the experimental data for the case of a capacitive circular microplates with an initial deflection. The increase of the static pressure leads to a shift in the resonance frequencies due to the increase in the stiffness of the plate. Also the initial deflection change the resonance frequencies due to the change in the effective gap distance. The developed model is an effective tool to predict the dynamic behavior of a microsystem under the effect of air film and with initial deflection.
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Helcig, Christian, Christian Teigeler, and Stefan aus der Wiesche. "Experimental Investigation of the Laminar Boundary Layer Flow on a Rotating Wavy Disk." In ASME 2016 Fluids Engineering Division Summer Meeting collocated with the ASME 2016 Heat Transfer Summer Conference and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/fedsm2016-7579.

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Since nearly one century, the flow on a flat rotating disk has provided the paradigm for studying rotating flows. For the laminar flow regime, a self-similar solution was obtained by von Kármán [6] in 1921, and a rather special feature of his exact solution of the Navier-Stokes equation is a constant boundary layer thickness not depending on the radial coordinate. A substantial modification of this canonical configuration is given by a wavy disk with a sinusoidal surface shape. Although axis-symmetric, no exact solution for the laminar flow on a wavy disk is known so far. In this study, detailed measurements of the velocity profiles were performed within the laminar boundary layer flow on a wavy disk. Based upon the experimental data, the potential of a self-similar solution approach for describing the resulting flow field was assessed. It was found that such an approach is useful for approximating the far-field solution but systematic deviations were observed in the vicinity of the disk origin.
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Sadri, Mehran, Davood Younesian, and Ebrahim Esmailzadeh. "Application of Variational Iteration Method in Nonlinear Free Vibration Analysis of Multi-Layered Nano-Scale Graphene Sheets." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38957.

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The nonlinear free vibration of multi-layered nano-scale graphene sheets is studied. Using the von Kármán and nonlocal continuum theories, large amplitude of vibration is included in the analysis as well as the size effect of nano-structure. The SSSS boundary condition is considered for the multi-layered graphene sheet and coupled nonlinear differential equations of motion of layers are taken into account based on Galerkin method. Variational iteration method (VIM) is employed as the solution procedure and nonlinear natural frequencies of the system are analytically determined. Two different geometries are taken into account and the analytical results are compared with frequencies obtained by numerical method. Finally, influence of geometrical parameters and amplitude of vibration on nonlinear frequencies of the system is examined.
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Fei, Yaying, Lihua Chen, Xiaozhi Zhang, and Wei Zhang. "Study on the Snap-Through Behavior of Bistable Plates." In ASME 2016 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/smasis2016-9113.

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This paper aims to analyze snap-through behavior of two-layer cross-ply bistable composite laminate square plates. The analyses consider the factors of laminate thickness, temperature and external applied force. In this study, the model was performed on the basis of the classical thin plate theory, the Von Kármán large deformation theory and Principle of Virtual Work. Afterwards the statics equilibrium equation was available. Subsequently the analysis was presented by adjusting the laminate thickness for these prior factors. Through the numerical simulations with Matlab® software, the curvatures in x-direction and y-direction were calculated to investigate the snap-through behavior. Two stable cylindrical configurations and an unstable saddle shape were given with different curvatures to show the equilibrium positions. Then the figures prove the external applied distributed force plays a vital role to the snap-through behavior. The results show that under macroscopic view, the ratio of side-length to thickness is three hundred or less, as the plates are thinner, the snap-through will appear more frequently, and the external forces will be less needed.
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Saadatnia, Zia, Ebrahim Esmailzadeh, and Davood Younesian. "Analytical Solutions for Nonlinear Free Vibration of Micro-Scale Timoshenko Beams." In ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-60598.

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Nonlinear free vibration of micro-beams based on the Timoshenko beam model is studied. The governing equations of motion using the strain gradient theory, Von Kármán strain tensors and Hamiltonian principle, are developed. The Galerkin method is applied to the governing equations and the coupled nonlinear ordinary differential equations of system are obtained. The variational iteration method is utilized to determine the time responses of the micro-beam and also a close form expression for the frequency-amplitude is found. The analytical solutions obtained for different values of parameters are compared with those found from different numerical methods. The effects of geometrical and physical parameters on the dynamics of micro-beam are also examined. Moreover, the analytical formulation for frequency ratio, i.e., the ratio of nonlinear natural frequency to the linear one is obtained and the sensitivity of this ratio to the variations of various parameters is evaluated. It is proved that the proposed solution methods and the results obtained are accurate and reliable when dynamics of such micro structures are studied.
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Hu, G. F., A. R. Damanpack, M. Bodaghi, and W. H. Liao. "Shape Adaptive Structures by 4D Printing." In ASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/smasis2017-3773.

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This paper introduces a 4D printing method to program shape memory polymers (SMPs) during fabrication process. Fused deposition modeling is employed to program SMPs during depositing the material. This approach is implemented to fabricate complicated polymeric structures by self-bending features without need of any post-programming. Experiments are conducted to demonstrate feasibility of one-dimensional (1D)-to 2D and 2D-to-3D self-bending. It is shown that 4D printed plate structures can transform into 3D curved shell structures by simply heating. A 3D macroscopic constitutive model is developed to predict thermo-mechanical behaviors of the printed SMPs. Governing equations are also established to simulate programming mechanism during printing process and shape change of self-bending structures. In this respect, a finite element formulation is developed considering von-Kármán geometric non-linearity and solved by implementing iterative Newton-Raphson scheme. The accuracy of the computational approach is checked with experimental results. It is shown that the structural-material model is capable of replicating the main features observed in the experiments.
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Pacciani, Roberto, Michele Marconcini, Andrea Arnone, and Francesco Bertini. "URANS Analysis of Wake-Induced Effects in High-Lift, Low Reynolds Number Cascade Flows." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69479.

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A URANS analysis of unsteady effects induced by incoming wakes in high-lift, low-Reynolds-number cascade flows has been carried out using a novel, transition-sensitive, turbulence model. It is based on the coupling of two additional transport equations, one for the so-called laminar kinetic energy (LKE) and one for a turbulence indicator function, with a low Reynolds number formulation of the Wilcox k-ω model. Two high-lift cascades (T106C and T2), recently tested at the von Kármán Institute in the framework of the two European research projects UTAT (Unsteady Transition in Axial Turbomachines) and TATMo (Turbulence and Transition Modelling for Special Turbomachinery Applications), were considered for the present study. The analyzed Reynolds number values span the whole range typically encountered in aero-engines low-pressure turbines operations, and both steady and periodically unsteady inflow conditions were considered. A detailed comparison between measurements and computations, in terms of blade surface isentropic Mach number distributions and cascade lapse rates will be presented and discussed. Results with the proposed model show its ability to predict the major effects of passing wakes on the boundary layer development and loss characteristics of high-lift cascades operating in LP-turbine conditions.
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Reports on the topic "Equation de von Kármán"

1

Banerjee, Tirtha, Frederik De Roo, and Rodman Linn. Revisiting Kelvin Helmholtz Instabilities and von Kármán Vortices in Canopy Turbulence. Office of Scientific and Technical Information (OSTI), October 2017. http://dx.doi.org/10.2172/1558041.

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