Sökning: "isotropic turbulence"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden isotropic turbulence.

  1. 1. Turbulence modulation effects caused by small droplets using one-dimensional-turbulence

    Författare :Marco Fistler; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiphase Flow; Droplets; one-dimensional-turbulence ODT ; Turbulence;

    Sammanfattning : This thesis presents a stochastic model to study turbulence modulation effects on gas phases caused by small droplets or more generally speaking particles to achieve a better understanding about the physics and with the aim to provide data for a subgrid-scale (SGS) model for Large-eddy-simulations. The one-dimensional-turbulence (ODT) model addresses one of the major issues for multiphase flow simulations, namely computational costs. LÄS MER

  3. 2. An Experimental Study of Reynolds Stress Closures in Shear Free and Weakly Sheared Turbulence

    Författare :Dag Aronson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; turbulence modelling; dissipation measurements; Reynolds stress closures; isotropic turbulence; anisotropic dissipation rate tensor; hot-wire anemometry; wall proximity effects; pressure strain rate correlations;

    Sammanfattning : The objective of this thesis work is to obtain data enabling evaluation of closure hypotheses used in the Reynolds stress transport (RST) equations. Special attention has been devoted to studies of flow fields with shear free and weakly sheared turbulence. LÄS MER

  4. 3. Mean Wind and Turbulence Conditions in the Boundary Layer above Forests

    Författare :Johan Arnqvist; Hans Bergström; Anna Rutgersson; Stefan Söderberg; Søren Larsen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wind power; Forest; Turbulence; Waves; Spectra; Wind model; Atmospheric stability; Vindkraft; Skog; Turbulens; Vågor; Spektra; Modell; Atmosfärisk stabilitet;

    Sammanfattning : As wind turbines have grown, new installation areas become possible. Placing wind turbines in forested landscapes introduce uncertainties to the wind resource estimation. LÄS MER

  5. 4. Suspensions of finite-size rigid particles in laminar and turbulent flows

    Författare :Walter Fornari; Luca Brandt; Jérémie Bec; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Suspensions; complex fluids; sedimentation; rheology; turbulence;

    Sammanfattning : Dispersed multiphase flows occur in many biological, engineering and geophysical applications. Understanding the behavior of suspensions is a difficult task. In the present work, we numerically study the behavior of suspensions of finite-size rigid particles in different flows. LÄS MER

  7. 5. Towards Improved Scale-Resolving Modeling and Simulations of Turbulent Flows

    Författare :Magnus Carlsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hybrid RANS-LES; Numerical methods; Synthetic Turbulence; Compressible flow; Scale-resolving simu- lation; High-order gradient reconstruction; Turbulence modelling;

    Sammanfattning : Scale-resolving simulations are viewed as powerful means for predicting complex turbulentflows, as often encountered in aeronautical applications. However, since turbulent scalesspan over a considerable range from the smallest Kolmogorov scales to the largest ofequivalence to configuration size, scale-resolving computations are often demandingon computational resources and, furthermore, on the underlying numerical methodsused in the simulations. LÄS MER