Sökning: "high order methods"

Visar resultat 1 - 5 av 2011 avhandlingar innehållade orden high order methods.

1. 1. Stable High-Order Finite Difference Methods for Aerodynamics

   Författare :Magnus Svärd; Jan Nordström; Thomas Hagstrom; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite difference methods; high-order accuracy; summation-by-parts; stability; energy estimates; finite volume methods; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Numerical Analysis;

   Sammanfattning : In this thesis, the numerical solution of time-dependent partial differential equations (PDE) is studied. In particular high-order finite difference methods on Summation-by-parts (SBP) form are analysed and applied to model problems as well as the PDEs governing aerodynamics. LÄS MER

3. 2. High order summation-by-parts methods in time and space

   Författare :Tomas Lundquist; Jan Nordström; Peter Eliasson; David A. Kopriva; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; summation-by-parts; time integration; stiff problems; weak initial conditions; high order methods; simultaneous-approximation-term; finite difference; discontinuous Galerkin; spectral methods; conservation; energy stability; complex geometries; non-conforming grid interfaces; interpolation;

   Sammanfattning : This thesis develops the methodology for solving initial boundary value problems with the use of summation-by-parts discretizations. The combination of high orders of accuracy and a systematic approach to construct provably stable boundary and interface procedures makes this methodology especially suitable for scientific computations with high demands on efficiency and robustness. LÄS MER

4. 3. A hybrid high order method for simulation of turbulent flow in complex geometries

   Författare :Arnim Brüger; KTH; []
   Nyckelord :Navier-Stokes; high order; spectral methods; curvilinear coordinates; approximate factorization; iterative methods; turbulence;

   Sammanfattning : .... LÄS MER

5. 4. High Order Finite Difference Methods in Space and Time

   Författare :Wendy Kress; Bertil Gustafsson; Gerald Warnecke; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite difference methods; Navier-Stokes equations; high order time discretization; deferred correction; stability; Numerical Analysis; Numerisk analys;

   Sammanfattning : In this thesis, high order accurate discretization schemes for partial differential equations are investigated. In the first paper, the linearized two-dimensional Navier-Stokes equations are considered. LÄS MER

7. 5. Active Control of Propeller-Induced Noise in Aircraft : Algorithms & Methods

   Författare :Sven Johansson; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; active control of sound; active noise control; anc; actuator individual normalized filtered-x lms; filtered-x lms algorithm; newton algorithm; complex lms; multireference algorithm; leaky lms; control effort weighting; feedforward control; feedback contro;

   Sammanfattning : In the last decade acoustic noise has become more and more regarded as a problem. In cars, boats, trains and aircraft, low-frequency noise reduces comfort. Lightweight materials and more powerful engines are used in high-speed vehicles, resulting in a general increase in interior noise levels. LÄS MER