Search for dissertations about: "LES turbulence model"

Showing result 1 - 5 of 73 swedish dissertations containing the words LES turbulence model.

2. 1. 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

4. 2. Assessment and Some Improvements of Hybrid RANS-LES Methods

   Author : Sebastian Arvidson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; LES; hybrid RANS-LES; zonal RANS-LES; embedded LES; PDH-LRN; log-layer mismatch; LES length scale; shock boundary-layer interaction;

   Abstract : Motivated by numerical analysis of a shock/boundary-layer interacting (SBLI) flow in a duct, where some typical existing hybrid RANS-LES methods become awkward to give accurate predictions of the shock-induced corner separation bubble, a new hybrid RANS-LES method, has been proposed. The model is based on a low-Reynolds-number (LRN) $k-\omega$ RANS model, which is one of the few models that are capable of giving reasonable predictions for the SBLI flow in RANS computations. READ MORE

5. 3. Turbulence-resolving Simulations of Swirling Flows

   Author : Ardalan Javadi; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Swirling Flow; URANS; Hydropower; Hybrid URANS-LES; SAS; Flow Control; Turbulence Modeling; Vortex Breakdown; DDES; LES;

   Abstract : A series of numerical investigations is undertaken using a wide range of turbulence mod-els including conventional and non-conventional URANS models, hybrid URANS-LESmethods and LES to capture a large variety of physical mechanisms that produce pres-sure pulsations in the swirling flows. The available knowledge about these pulsations,which are usual in hydropower, are still far from complete. READ MORE

6. 4. Turbulence-droplet interaction modelled by One-Dimensional-Turbulence

   Author : Marco Fistler; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; One-Dimensional-Turbulence ODT ; Multiphase Flow; Turbulence; Droplets;

   Abstract : A stochastic model to study droplet/particle influence on the gas phase using the One-Dimensional-Turbulence model (ODT) is evaluated. To address one of the major problems for multiphase flow simulations, namely computational costs, the dimension-reduced model is used with the goal of predicting certain classes of these flows more efficiently. READ MORE

7. 5. The One-Dimensional Turbulence Model Applied to Spray Atomization

   Author : Amirreza Movaghar; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Primary breakup; Turbulence; One Dimensional Turbulence ODT ;

   Abstract : Numerical simulation of the spray behavior is an important part of engine research and is critical for combustion optimization. Successful implementation of the advanced modeling tools for sprays is strongly dependent on our current understanding of the physical processes involved. READ MORE