Search for dissertations about: "decaying turbulence"

Showing result 1 - 5 of 8 swedish dissertations containing the words decaying turbulence.

2. 1. Statistical characteristics of two-dimensional and quasigeostrophic turbulence

   Author : Andreas Vallgren; Erik Lindborg; Johan Nilsson; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; two-dimensional turbulence; decaying turbulence; quasigeostrophic turbulence; direct numerical simulation DNS ; coherent vortices; energy cas- cade; enstrophy cascade; intermittency; massively parallel simulations; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos;

   Abstract : Two codes have been developed and implemented for use on massively parallelsuper computers to simulate two-dimensional and quasigeostrophic turbulence.The codes have been found to scale well with increasing resolution and width ofthe simulations. READ MORE

4. 2. Dynamic properties of two-dimensional and quasi-geostrophic turbulence

   Author : Andreas Vallgren; Erik Lindborg; Guido Boffetta; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; two-dimensional turbulence; decaying turbulence; quasi-geostrophic turbulence; direct numerical simulation DNS ; coherent vortices; energy cascade; enstrophy cascade; intermittency; massively parallel simulations; locality iii; Non-linear dynamics; chaos; Icke-linjär dynamik; kaos;

   Abstract : Two codes have been developed and implemented for use on massively parallelsuper computers to simulate two-dimensional and quasi-geostrophic turbulence.The codes have been found to scale well with increasing resolution and width ofthe simulations. READ MORE

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

   Author : Magnus Carlsson; Chalmers tekniska högskola; []
   Keywords : 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;

   Abstract : 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. READ MORE

6. 4. Development of Numerical Methods for Accurate and Efficient Scale-Resolving Simulations

   Author : Magnus Carlsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-order gradient reconstruction; Hybrid RANS-LES; Scale-resolving simulation; Synthetic Turbulence; Numerical methods; Turbulence modelling;

   Abstract : Hybrid RANS (Reynolds-Averaged Navier-Stokes)-LES (Large-Eddy Simulation) techniques are considered to be sufficiently accurate and computationally affordable for the aeronautical industry. Scale-resolving simulations is a powerful tool that can accurately predict complex unsteady compressible high-Reynolds-number turbulent flows, as often encountered aeronautical applications. READ MORE

7. 5. Methodologies for RANS-LES interfaces in turbulence-resolving simulations

   Author : Sebastian Arvidson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; zonal RANS-LES; aeronautics; RANS-LES interfaces; Hybrid RANS-LES; grey-area mitigation; log-layer mismatch; embedded LES; LES length scale; LES;

   Abstract : Hybrid Reynolds-Average Navier-Stokes (RANS)-Large-Eddy Simulations (LES) techniques are now seen by the aeronautical industry as the most promising turbulence-resolving approaches for complex high-Reynolds-number turbulent flows with regard to cost and accuracy. However, connecting RANS and LES simulated flows is a challenging task and needs special attention in order to increase simulation robustness and accuracy. READ MORE