Sökning: "initial value problems"

Visar resultat 6 - 10 av 72 avhandlingar innehållade orden initial value problems.

1. 6. Redesigning Together : Relearning Roles and the Value of Materials in the Overproduction of Fashion

   Författare :Amanda Curtis; Högskolan i Borås; []
   Nyckelord :community of practice; do-it-yourself; do-it-together; participatory design; social production; sustainable fashion; value creation; Textil och mode generell ; Textiles and Fashion General ;

   Sammanfattning : What could cause greater upheaval in any system of trade than the consumer becoming the producer? Even though there is a vast amount of information concerning the negative environmental and social impact that the overproduction of fashion contributes to, the industry still manages to attract and make more people into consumers as they are playing on the human need and desire for renewal. The purpose of this study is to learn more about collaborative approaches on a grassroots level that could contribute to reducing the growing mountain of second-hand garments created by this overproduction. LÄS MER

3. 7. 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. 8. Summation-by-parts formulations for flow problems

   Författare :Fredrik Laurén; Jan Nordström; Andrew Ross Winters; Martin Kronbichler; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Many problems in engineering and physics can be described by partial differential equations (PDEs). Augmented with proper initial and boundary conditions, the PDE forms an initial-boundary value problem (IBVP). An IBVP is said to be well-posed if a unique solution bounded by the given data exists. LÄS MER

5. 9. Investigations of problems related to the choice of the initial state for numerical weather prediction models

   Författare :Stefan Gollvik; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In numerical prediction models, where the wind and mass fields are described as free variables (so called primitive equation models), the initial state has to be carefully chosen, to avoid spurious oscillations in the forecast. This thesis deals with this initialization problem. LÄS MER

7. 10. 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