Implementation of k-epsilon turbulence models in a two dimensional parallel navier-stokes solver on hybrid grids

Kalkan, Onur Ozan
In this thesis, the popular k-ε turbulence model is implemented on a parallel, 2-dimensional, explicit, density-based, finite volume based Navier-Stokes solver works on hybrid grids, HYP2D. Among the other versions available in the open literature, standard version of the k-ε turbulence mode is studied. Launder-Spalding and Chieng-Launder wall functions are adapted to the turbulence model in order to investigate the effects of the strong gradients in the vicinity of the wall on the turbulence. In order to include the low-Reynolds-number effects near the wall Abid’s and Abe-Kondoh-Nagano near wall models are also implemented. Flow over turbulent flat plate and RAE 2822 airfoil are studied for validation of the implementation. After the results show that the implementation is successful according to experimental data and other numerical solutions, NACA 0012 airfoil is simulated at different flow conditions and the effects of turbulence model on the results are discussed. The ability of simulating the turbulent flow with accuracy is acquired to HYP2D solver.


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In this thesis a microcontroller core is developed in an FPGA. Its instruction set is compatible with the microcontroller PIC16XX series by Microchip Technology. The microcontroller employs a RISC architecture with separate busses for instructions and data. Our goal in this research is to implement and evaluate the design in the FPGA. Increasing performance and gate capacity of recent FPGA devices permits complex logic systems to be implemented on a single programmable device. Such a growing complexity dema...
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For output-feedback control of linear time-varying (LTV) and nonlinear systems, this paper focuses on control based on the forward propagating Riccati equation (FPRE). FPRE control uses dual difference (or differential) Riccati equations that are solved forward in time. Unlike the standard regulator Riccati equation, which propagates backward in time, forward propagation facilitates output-feedback control of both LTV and nonlinear systems expressed in terms of a state-dependent coefficient (SDC). To invest...
Time filtered second order backward Euler method for EMAC formulation of Navier-Stokes equations
Demir, Medine; Çıbık, Aytekin; Kaya Merdan, Songül (2022-12-15)
© 2022 Elsevier Inc.This paper considers the backward Euler based linear time filtering method for the developed energy-momentum-angular momentum conserving (EMAC) formulation of the time dependent-incompressible Navier-Stokes equations in the case of weakly enforced divergence constraint. The method adds time filtering as a post-processing step to the EMAC formulation to enhance the accuracy and to improve the approximate solutions. We show that in comparison with the Backward-Euler based EMAC formulation ...
Multi-symplectic integration of coupled non-linear Schrodinger system with soliton solutions
AYDIN, AYHAN; Karasözen, Bülent (2009-01-01)
Systems of coupled non-linear Schrodinger equations with soliton solutions are integrated using the six-point scheme which is equivalent to the multi-symplectic Preissman scheme. The numerical dispersion relations are studied for the linearized equation. Numerical results for elastic and inelastic soliton collisions are presented. Numerical experiments confirm the excellent conservation of energy, momentum and norm in long-term computations and their relations to the qualitative behaviour of the soliton sol...
Citation Formats
O. O. Kalkan, “Implementation of k-epsilon turbulence models in a two dimensional parallel navier-stokes solver on hybrid grids,” M.S. - Master of Science, Middle East Technical University, 2014.