Sökning: "Mesh dependence"

Visar resultat 11 - 15 av 15 avhandlingar innehållade orden Mesh dependence.

1. 11. On the representation of precipitation in high-resolution regional climate models

   Författare :Petter Lind; Erik Kjellström; Michael Tjernström; Jan Erik Haugen; Anna Rutgersson; Abdel Hannachi; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Regional climate modeling; high-resolution; convection parameterization; precipitation; extremes; statistical analysis; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography; meteorologi; Meteorology;

   Sammanfattning : Weather and climate models applied with sufficiently fine mesh grids to enable a large part of atmospheric deep convection to be explicitly resolved have shown a significantly improved representation of local, short-duration and intense precipitation events compared to coarser scale models. In this thesis, two studies are presented aimed at exploring the dependence of horizontal resolution and of parameterization of convection on the simulation of precipitation. LÄS MER

3. 12. Wind turbine simulations using spectral elements

   Författare :Elektra Kleusberg; Dan Henningson; Philipp Schlatter; Stefan Ivanell; Johan Meyers; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind turbine; wakes; wake interaction; computational fluid dynamics; actuator line method; spectral elements; free-stream turbulence; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : Understanding the flow around wind turbines is a highly relevant research question due to the increased interest in harvesting energy from renewable sources. This thesis approaches the topic by means of numerical simulations using the actuator line method and the incompressible Navier–Stokes equations in the spectral element code Nek5000. LÄS MER

4. 13. Robust preconditioning methods for algebraic problems, arising in multi-phase flow models

   Författare :Xin He; Maya Neytcheva; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : The aim of the project is to construct, analyse and implement fast and reliable numerical solution methods to simulate multi-phase flow, modeled by a coupled system consisting of the time-dependent Cahn-Hilliard and incompressible Navier-Stokes equations with variable viscosity and variable density. This thesis mainly discusses the efficient solution methods for the latter equations aiming at constructing preconditioners, which are numerically and computationally efficient, and robust with respect to various problem, discretization and method parameters. LÄS MER

5. 14. Experimental Studies of Complex Flows through Image-Based Techniques

   Författare :Gabriele Bellani; FredrIk Lundell; James Olsen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering mechanics; Teknisk mekanik;

   Sammanfattning : This thesis deals with the development of experimental techniques for the study of complex flows inspired to a large extent by the papermaking process. In particular one part of this thesis is devoted to the development of laboratory experiments based on index-of-refraction matching and imaging techniques to study the behavior of dilute and concentrated suspension of elongated particles. LÄS MER

7. 15. Numerical predictions and measurement of non-isothermal airflows : evaluation of buoyant wall jets and airflow through large openings

   Författare :Tobias Törnström; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : How can we attain a good indoor climate and at the same time reduce energy consumption? These issues are of particular interest in countries with cold climates, where the need for heating is large. It is important to design a HV AC (Heating, Ventilation and Air Conditioning) system that achieves a desirable indoor climate, where discomfort due to draft and thermal discomfort is avoided. LÄS MER