Browsing by Author "Wagner, Siegfried"

Filter results by typing the first few letters
Now showing 1 - 3 of 3
  • Thumbnail Image
    ItemOpen Access
    Computation of subsonic and transonic helicopter rotor flow using Euler equations
    (1988) Krämer, Ewald; Hertel, J.; Wagner, Siegfried
    A procedure for the computation of transonic steady and unsteady flow around helicopter rotors is presented. The algorithm is based on the Euler equations and allows the computation of anisotropic rotational flow and thus an implicitly accurate calculation of shocks. In addition the capturing of the rotor wake and the tip vortex is provided for arbitrary tip shapes. The code for the computation of steady, fully 3-D rotor flow is derived from the EUFLEX procedure originated by A. Eberle, that has successfully been applied to a lot of fixed wing configurations up to now. A finite-volume scheme based on the method of characteristic flux averaging solves the Euler equations formulated in the conservation form. The discretizatlon of the flow field is carried out in two different manners concerning the grid topology and the size of the physical domain. Calculations are presented for a non-lifting case and for a helicopter rotor in hover. The comparisons of the method in its present stage show good agreement with experimental data.
  • Thumbnail Image
    ItemOpen Access
    An innovative algorithm to accurately solve the Euler equations for rotary wing flow
    (1992) Wagner, Siegfried; Krämer, Ewald
    Due to the ability of Euler methods to treat rotational, nonisentropic flows and also to correctly transport on the rotation embedded in the flow field it is possible to correctly represent the inflow conditions on the blade in the stationary hovering flight of a helicopter, which are significantly influenced by the tip vortices (blade-vortex interaction) of all blades. It is shown that also the very complex starting procedure of a helicopter rotor can be very well described by a simple Euler method that is to say without a wake model. The algorithm based on the procedure is part of category upwind schemes, in which the difference formation orientates to the actual, local flow state that is to say to the typical distrubance expansion direction. Hence, the artificial dissipation required for the numerical stability is included in a natural way adapted to the real flow state over the break-up error of the difference equation and has not to be included from outside. This makes the procedure robust. An implicit solution algorithm is used, where the invertation of the coefficient matrix is carried out by means of a Point-Gauss-Seidel relaxation.
  • Thumbnail Image
    ItemOpen Access
    Jahresfeier 2005 der Universität Stuttgart
    (2007) Fritsch, Dieter; Leibinger, Berthold; Leicht, Dieter; Jacobi, Robert; Eligehausen, Rolf; Schlaich, Jörg; Dressel, Martin; Bertagnolli, Helmut; Wagner, Siegfried; Pritschow, Günter; Komarek, Kurt Ludwig; Pertschi, Ottmar (Herausgeber)
    Inhalt: Fritsch, Dieter: Begrüßung (S. 9 - 16); Leibinger, Berthold: Grußwort (S. 17 - 18); Leicht, Dieter: Grußwort (S. 19 - 22); Jacobi, Robert: Grußwort (S. 23 - 26); Fritsch, Dieter: Die Landkarte im Spannungsfeld von Internet und Multimedia (Festvortrag) (S. 29 - 46); Eligehausen, Rolf: Laudatio auf Prof. Dr. h. c. Reinhold Würth (S. 47 - 52); Schlaich, Jörg: Laudatio auf Prof. Dr.-Ing. Walter H. Dilger (S. 53 - 56); Dressel, Martin: Laudatio auf Prof. Dr. Denis Jérome (S. 57 - 62); Bertagnolli, Helmut: Laudatio auf Prof. Dr. phil. Kurt Ludwig Komarek (S. 63 - 66); Wagner, Siegfried: Laudatio auf Prof. Dr. Egon Krause Ph. D. (S. 67 - 72); Pritschow, Günter: Laudatio auf Prof. Dr. Jan Koch (S. 73 - 78); Komarek, Kurt Ludwig: Dankesworte (S. 79 - 80); Aus der Presse (S. 81 - 82)