Sökning: "finite differences"

Visar resultat 11 - 15 av 142 avhandlingar innehållade orden finite differences.

1. 11. Hybrid Methods for Unsteady Fluid Flow Problems in Complex Geometries

   Författare :Jing Gong; Jan Nordström; Gunilla Efraimsson; Mark H. Carpenter; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hybrid methods; finite difference methods; finite volume methods; coupling procedure; stability; efficiency; artificial dissipation; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Beräkningsvetenskap med inriktning mot numerisk analys;

   Sammanfattning : In this thesis, stable and efficient hybrid methods which combine high order finite difference methods and unstructured finite volume methods for time-dependent initial boundary value problems have been developed. The hybrid methods make it possible to combine the efficiency of the finite difference method and the flexibility of the finite volume method. LÄS MER

3. 12. A new high-order method for direct numerical simulations of turbulent wall-bounded flows

   Författare :Peter Lenaers; Arne Johansson; Hans Kuerten; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Incompressible wall-bounded flows; direct numerical simulations; high-order; compact finite differences; collocated grid; influence matrix method;

   Sammanfattning : A new method to perform direct numerical simulations of wall-bounded flows has been developed and implemented. The method uses high-order compact finite differences in wall-normal (for channel flow) or radial direction (for pipe flow) on a collocated grid, which gives high-accuracy results without the effectfof filtering caused by frequent interpolation as required on a staggered grid. LÄS MER

4. 13. Computation of Thermal Development in Injection Mould Filling, based on the Distance Model

   Författare :Per-Åke Andersson; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; thermoplastic materials; finite element FEM ; finite difference FD ; Newton-Mysovskii theorem; Moldflow Mfl ; Cadmould Cmd ; MATHEMATICS; MATEMATIK;

   Sammanfattning : The heat transfer in the filling phase of injection moulding is studied, based on Gunnar Aronsson’s distance model for flow expansion ([Aronsson], 1996).The choice of a thermoplastic materials model is motivated by general physical properties, admitting temperature and pressure dependence. LÄS MER

5. 14. Fourth order symmetric finite difference schemes for the wave equation

   Författare :Abraham Zemui; Bertil Gustafsson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Numerical Analysis; Numerisk analys;

   Sammanfattning : The solution of the acoustic wave equation in one space dimension is studied. The PDE is discretized using finite element approximation. A cubic piecewise Lagrange polynomial is used as basis. Consistent finite element and lumped mass schemes are obtained. LÄS MER

7. 15. A Finite Element Model of the Human Head for Simulation of Bone-conducted Sound

   Författare :You Chang; Stefan Stenfelt; Namkeun Kim; Frank Böhnke; Linköpings universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; bone conduction; finite element model，bone-conduction devices;

   Sammanfattning : Bone conduction is usually understood as the hearing sensation based on the vibrations of the skull bone and surrounding tissues. The fact that vibration of the skull bones can result in a sound percept has been known for a long time. However, it is difficult to give a general definition of BC sound. LÄS MER