Download or read book Calcul d coulements supersoniques pour r solution des quations de Navier Stokes parabolis es written by Hugues Deniau and published by . This book was released on 1996 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dans le cadre de la prévision d'un écoulement supersonique par résolution des équations de Navier-Stokes Parabolisées (PNS), trois thèmes sont successivement abordés. Moyennant un traitement particulierdu gradient de pression longitudinal, le système PNS est de nature hyperbolique-parabolique. Une méthode de marche en espace a été envisagée. La discrétisation de la partie convective est essentielle pour assurer la robustesse et la précision du schéma. L'utilisation de schémas décentrés de type Roe dans la région subsonique s'avère très intéressante pour la robustesse et n'engendre pas de perte de précision. Le second thème concerne la modélisation de la turbulence avec pour double objectif de tester des modèles de turbulences éprouvés (aspect industriel) et d'étudier des modèles élaborés et récents (aspect recherche). Après avoir identifié les lacunes des modèles algébriques, une comparaison des performances des modèles à deux équations de transport à une ou deux couches ou aux tensions de Reynolds sur les plans numérique et relatif à la qualité des résultats est présentée. Un traitement de la région de proche paroi permettant de réduire la sensibilité au maillage monocouches a été développé. Pour les modèles aux tensions de reynolds, l'accent porte sur la rpise en compte des effets de paroi dans la modélisation des termes sources des équations de transport et plus précisément du terme de redistribution d'énergie. Deux grandes familles de modèles ont ainsi été identifiées selon la nature de l'amortissement pariétal. En dépit d'une plus faible robustesse, les modèles aux tensions de Reynolds se sont révélés mieux à même de prévoir un écoulement tourbillonnaire. Les différents modèles ainsi que les modifications apportées ont été testés dans le cas d'un écoulement se développant sur un ogive-cylindre. Enfin, le dernier thème concerne le traitement des zones subsoniques étendues. Une procédure mixte permettant de calculer un écoulement par résolution des équations de Navier-Stokes ou PNS a été développé. La détection automatique des zones de l'écoulement où les hypothèses de parabolisation ne sont plus valables a nécessité la mise au point de critères.

Download or read book Calculs d coulements supersoniques turbulents par r solution des quations de Navier Stokes parabolis es written by Jean-Marc Moschetta and published by . This book was released on 1991 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: UNE METHODE DE RESOLUTION DES EQUATIONS DE NAVIER-STOKES PARABOLISEES (PNS) A ETE ELABOREE POUR CALCULER DES ECOULEMENTS SUPERSONIQUES VISQUEUX BIDIMENSIONNELS ET TRIDIMENSIONNELS. UNE STRATEGIE DE MARCHE EN ESPACE EST MISE EN UVRE AU MOYEN D'UN ALGORITHME IMPLICITE BASE SUR LE SCHEMA DECENTRE DU PREMIER ORDRE DE ROE ET DU SCHEMA TVD DU SECOND ORDRE D'OSHER-CHAKRAVARTHY. LE MODELE ALGEBRIQUE DE BALDWIN-LOMAX PERMET DE RENDRE COMPTE DES EFFETS DE LA TURBULENCE COMPRESSIBLE TANDIS QUE LE PROBLEME DE L'ADAPTATION DU MODELE K-EPSILON FORTEMENT COUPLE AUX EQUATIONS PNS EST ABORDE. PLUSIEURS CALCULS DE VALIDATION ALLANT DE L'ECOULEMENT BIDIMENSIONNEL SUR LA PLAQUE PLANE A L'ECOULEMENT TRIDIMENSIONNEL AUTOUR D'UN FUSELAGE DE MISSILE EN INCIDENCE COMPORTANT DES DECOLLEMENTS TRANSVERSAUX SONT DECRITS ET PERMETTENT DE DEMONTRER LA ROBUSTESSE ET LA QUALITE DE LA METHODE

Download or read book Advances in Numerical Fluid Dynamics written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel and published by . This book was released on 1973 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Calcul d coulements compressibles par m thodes spectrales avec ajustement du choc written by Jean Claudel and published by . This book was released on 1991 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: ON S'INTERESSE AU DEVELOPPEMENT DE METHODES NUMERIQUES APPLIQUEES A LA SIMULATION D'ECOULEMENTS SUR LES AVANT-CORPS EN REGIME SUPERSONIQUE, INCLUANT DONC LA PRESENCE D'UN CHOC. EN RAISON DE LEUR PRECISION, DES METHODES SPECTRALES SONT UTILISEES POUR DISCRETISER LA SOLUTION EN ESPACE. AFIN D'EXPLOITER AU MIEUX LES AVANTAGES DE CE TYPE DE METHODES, ON TRAVAILLE DANS UN DOMAINE OU LES INCONNUES SE COMPORTENT DE MANIERE REGULIERE. A CET EFFET, LA SURFACE DE CHOC EST PRISE EN COMPTE PAR UNE METHODE D'AJUSTEMENT DU CHOC, GRACE A LAQUELLE LE CHOC EST CONSIDERE COMME UNE FRONTIERE DU DOPMAINE DE CALCUL; ON S'EST DE PLUS BORNES A L'ETUDE DE CORPS REGULIERS (ELLIPSES) PERMETTANT L'OBTENTION D'UN MAILLAGE REGULIER. LES PROBLEMES TRAITES ADMETTENT UN ETAT STATIONNAIE UNIQUE, OBTENU COMME LA LIMITE, POUR UN TEMPS TENDANT VERS L'INFINI, D'UN SYSTEME TRAITE DE MANIERE INSTATIONNAIRE. LE BUT N'EST PAS ICI DE DECRIRE FIDELEMENT L'HISTORIQUE DE LA CONVERGENCE DE LA SOLUTION, MAIS D'ACCELERER LA RECHERCHE DE LA STATIONNARITE. ON INTRODUIT UN SCHEMA IMPLICITE COMPORTANT UNE PHASE DE STABILISATION EN DIFFERENCES FINIES QUI CONSERVE LA PRECISION SPECTRALE, TOUT EN PERMETTANT DE S'AFFRANCHIR DES CONTRAINTES DE TEMPS D'EXECUTION INFORMATIQUE INHERENTES AUX METHODES SPECTRALES POUR CETTE CLASSE DE PROBLEMES. AFIN D'EN DEFINIR LES LIMITES D'UTILISATION, CE SCHEMA EST TESTE SUR PLUSIEURS EXEMPLES TEST MONODIMENSIONNELS. IL EST ENSUITE APPLIQUE A LA RESOLUTION D'ECOULEMENTS BIDIMENSIONNELS NON VISQUEUX (EQUATIONS D'EULER) OU VISQUEUX (EQUATIONS DE NAVIER-STOKES) OU L'ON MET EN EVIDENCE SON INTERET ET SES IFFICULTES DE MISE EN UVRE

Download or read book Government reports annual index written by and published by . This book was released on 199? with total page 1014 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book RESOLUTION DES EQUATIONS DE NAVIER STOKES TRIDIMENSIONNELLES written by PATRICK.. QUEUTEY and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL CONCERNE LA RESOLUTION NUMERIQUE DES EQUATIONS DE NAVIER-STOKES POUR UN ECOULEMENT INCOMPRESSIBLE TURBULENT. POUR UN CHOIX DE COORDONNEES CURVILIGNES, LA THESE SE DIVISE EN DEUX PARTIES (PREMIERE PARTIE: FORMULATION CONVECTIVE; DEUXIEME PARTIE: FORMULATION CONSERVATIVE). LA FORMULATION CONVECTIVE EST TRAITEE PAR LE MODE PARTIELLEMENT PARABOLIQUE ET LE COUPLAGE VITESSE-PRESSION UTILISE UNE METHODE DE CORRECTION DE PRESSION (PROCEDURE SIMPLER). LE SOLVEUR DE PRESSION EMPLOI UN ALGORITHME DE GRADIENTS CONJUGUES PRECONDITIONNE PAR UN LU INCOMPLET OU LES INVERSIONS SONT REALISEES PAR DES SERIES DE NEUMANN A NOMBRE DE TERMES FINIE. DEUX APPLICATIONS SONT CONSIDEREES. L'UNE EST LE PROBLEME AXISYMETRIQUE DE L'INTERACTION HELICE-CARENE (EXPERIENCES DU DTRC) OU LE PROPULSEUR EST MODELISE PAR UNE THEORIE DE DISQUE ACTUATEUR. L'AUTRE (EXPERIENCES DU DLR) CORRESPOND A L'ECOULEMENT TURBULENT AUTOUR DE L'ELLIPSOIDE DE REVOLUTION A 10 DEGRES D'IUNCIDENCE (RE=7.2 MILLIONS). LES COMPARAISONS SONT EN ACCORD AVEC LES EXPERIENCES POUR LE PREMIER CAS ET METTENT EN EVIDENCE, DANS LE DEUXIEME CAS, LE BESOIN DE SE DEBARASSER DE CONDITIONS INITIALES ET LES PROBLEMES DE CONVERGENCE LIES A LA TECHNIQUE DE CORRECTION DE PRESSION. CELA JUSTIFIE LE DEVELOPPEMENT DE LA FORMULATION CONSERVATIVE. CETTE FORMULATION REPOSE SUR UN TRAITEMENT ELLIPTIQUE, LA TECHNIQUE DE CORRECTION DE PRESSION SUIT ALORS L'APPROCHE DE LA PROCEDURE PISO. LES CALCULS SONT MENES POUR L'ECOULEMENT LAMINAIRE COMPLET AUTOUR DE L'ELLIPSOIDE DE REVOLUTION A 10 DEGRES D'INCIDENCE (RE=1.6 MILLIONS). LES RESULTATS SONT MEILLEURS MALGRE UN MANQUE DE NOMBRE DE POINTS DE DISCRETISATION. CE TRAVAIL EVOQUE AUSSI (EN ANNEXES) LES PROBLEMES INHERENTS A LA DISCRETISATION DES EQUATIONS DE QUANTITE DE MOUVEMENT ET PROPOSE QUELQUES TECHNIQUES POUR AMELIORER LA QUALITE DES SCHEMAS NUMERIQUES

Download or read book SCHEMAS CENTRES A DEUX ET TROIS NIVEAUX DE TEMPS APPLICATIONS AUX EQUATIONS DE NAVIER STOKES EN REGIME SUPERSONIQUE written by Gilles Lacombe and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: L'ETUDE CONCERNE LE DEVELOPPEMENT ET L'ANALYSE DE METHODES NUMERIQUES IMPLICITES CENTREES DESTINEES AUX EQUATIONS DE NAVIER-STOKES REGISSANT LES ECOULEMENTS DE FLUIDES COMPRESSIBLES. LA METHODE DE BASE, DERIVEE DU SCHEMA DE LERAT POUR LES ECOULEMENTS DE FLUIDES NON VISQUEUX, EST PRESENTEE ET ANALYSEE EN UNE PUIS DEUX DIMENSIONS D'ESPACE. ON EXPOSE EN PARTICULIER UNE ETUDE DETAILLEE DE L'INFLUENCE DE DIVERS MODES DE FACTORISATION DE LA PARTIE IMPLICITE SUR CES PROPRIETES DE STABILITE ET DE CONVERGENCE VERS UN ETAT STATIONNAIRE. LA METHODE EST ENSUITE APPLIQUEE A DES CALCULS D'ECOULEMENTS SUPERSONIQUES LAMINAIRES SUR UNE RAMPE DE COMPRESSION. UNE DEUXIEME PARTIE EST CONSACREE A L'ELABORATION (A PARTIR D'UNE ETUDE LINEAIRE SCALAIRE SYSTEMATIQUE DES SCHEMAS A TROIS POINTS ET TROIS NIVEAUX DE TEMPS DANS LE CAS HYPERBOLIQUE) ET A L'ANALYSE D'UNE NOUVELLE VERSION A TROIS NIVEAUX DE TEMPS DE LA METHODE PRECEDENTE, DU MEME ORDRE DE PRECISION QUE CELLE-CI MAIS PLUS DISSIPATIVE ET DONC PLUS ROBUSTE. LA NOUVELLE METHODE EST TESTEE SUR UN CALCUL D'ECOULEMENT SUPERSONIQUE LAMINAIRE AUTOUR D'UNE DOUBLE ELLIPSE

Download or read book Vortex Flows and Related Numerical Methods written by J.T. Beale and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many important phenomena in fluid motion are evident in vortex flow, i.e., flows in which vortical structures are significant in determining the whole flow. This book, which consists of lectures given at a NATO ARW held in Grenoble (France) in June 1992, provides an up-to-date account of current research in the study of these phenomena by means of numerical methods and mathematical modelling. Such methods include Eulerian methods (finite difference, spectral and wavelet methods) as well as Lagrangian methods (contour dynamics, vortex methods) and are used to study such topics as 2- or 3-dimensional turbulence, vorticity generation by solid bodies, shear layers and vortex sheets, and vortex reconnection. For researchers and graduate students in computational fluid dynamics, numerical analysis, and applied mathematics.

Download or read book A Selection of Test Cases for the Validation of Large eddy Simulations of Turbulent Flows written by and published by . This book was released on 1998 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1987 with total page 1264 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spectral Methods for Incompressible Viscous Flow written by Roger Peyret and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: This well-written book explains the theory of spectral methods and their application to the computation of viscous incompressible fluid flow, in clear and elementary terms. With many examples throughout, the work will be useful to those teaching at the graduate level, as well as to researchers working in the area.

Download or read book Numerical Approximation of Hyperbolic Systems of Conservation Laws written by Edwige Godlewski and published by Springer Nature. This book was released on 2021-08-28 with total page 846 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph is devoted to the theory and approximation by finite volume methods of nonlinear hyperbolic systems of conservation laws in one or two space variables. It follows directly a previous publication on hyperbolic systems of conservation laws by the same authors. Since the earlier work concentrated on the mathematical theory of multidimensional scalar conservation laws, this book will focus on systems and the theoretical aspects which are needed in the applications, such as the solution of the Riemann problem and further insights into more sophisticated problems, with special attention to the system of gas dynamics. This new edition includes more examples such as MHD and shallow water, with an insight on multiphase flows. Additionally, the text includes source terms and well-balanced/asymptotic preserving schemes, introducing relaxation schemes and addressing problems related to resonance and discontinuous fluxes while adding details on the low Mach number situation.

Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Download or read book African Doctorates in Mathematics written by and published by Lulu.com. This book was released on 2007 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents a catalogue of over 2000 doctoral theses by Africans in all fields of mathematics, including applied mathematics, mathematics education and history of mathematics. The introduction contains information about distribution by country, institutions, period, and by gender, about mathematical density, and mobility of mathematicians. Several appendices are included (female doctorate holders, doctorates in mathematics education, doctorates awarded by African universities to non-Africans, doctoral theses by non-Africans about mathematics in Africa, activities of African mathematicians at the service of their communities). Paulus Gerdes compiled the information in his capacity of Chairman of the African Mathematical Union Commission for the History of Mathematics in Africa (AMUCHMA). The book contains a preface by Mohamed Hassan, President of the African Academy of Sciences (AAS) and Executive Director of the Academy of Sciences for the Developing World (TWAS). (383 pp.)

Download or read book Mathematical Reviews written by and published by . This book was released on 1981 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiscale and Multiresolution Approaches in Turbulence written by Pierre Sagaut and published by World Scientific. This book was released on 2013 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book aims to provide the reader with an updated general presentation of multiscale/multiresolution approaches in turbulent flow simulations. All modern approaches (LES, hybrid RANS/LES, DES, SAS) are discussed and recast in a global comprehensive framework. Both theoretical features and practical implementation details are addressed. Some full scale applications are described, to provide the reader with relevant guidelines to facilitate a future use of these methods.

Download or read book Computational Fluid Dynamics and Reacting Gas Flows written by Bjorn Engquist and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: This IMA Volume in Mathematics and its Applications COMPUTATIONAL FLUID DYNAMICS AND REACTING GAS FLOWS is in part the proceedings of a workshop which was an integral part of the 1986-87 IMA program on SCIENTIFIC COMPUTATION. We are grateful to the Scientific Committee: Bjorn Engquist (Chairman), Roland Glowinski, Mitchell Luskin and Andrew Majda for planning and implementing an exciting and stimulating year-long program. We especially thank the Workshop Organizers, Bjorn Engquist, Mitchell Luskin and Andrew Majda, for organizing a workshop which brought together many of the leading researchers in the area of computational fluid dynamics. George R. Sell Hans Weinberger PREFACE Computational fluid dynamics has always been of central importance in scientific computing. It is also a field which clearly displays the essential theme of interaction between mathematics, physics, and computer science. Therefore, it was natural for the first workshop of the 1986- 87 program on scientific computing at the Institute for Mathematics and Its Applications to concentrate on computational fluid dynamics. In the workshop, more traditional fields were mixed with fields of emerging importance such as reacting gas flows and non-Newtonian flows. The workshop was marked by a high level of interaction and discussion among researchers representing varied "schools of thought" and countries.