Implementation and assessment of Hellsten explicit algebraic Reynolds stress k-omega model

Download
2022-9
İlhan, Umut
Turbulence modeling is one of the most challenging aspects of Computational Fluid Dynamics (CFD). The choice of turbulence model affects the accuracy and computational cost of the CFD analyses. Linear Eddy Viscosity Models (LEVMs) are commonly used in industrial CFD applications due to their low computational cost and ease of convergence. However, they often fail to model complex flow structures. More advanced models, such as Reynolds Stress Transport Models (RSTMs), have better performance for capturing the complex flow physics. RSTMs suffer from convergence difficulties and high computational requirements. In order to combine the computational cost advantage of LEVMs with the accurate prediction of complex flow physics of RSTMs, Explicit Algebraic Reynolds Stress Models (EARSMs) have been introduced. Hellsten utilizes Wallin-Johansson Explicit Algebraic Reynolds Stress Model (WJ-EARSM) as a constitutive model and Menter’s Shear Stress Transport Model as a baseline model for k and ω transport equations. Hellsten slightly modified the transport model equations and calibrated the model coefficients to implement WJ-EARSM on the base turbulence model. This model is claimed to be favorable by having similar computational cost and coding advantages to the SST and a similar level of accuracy to the WJ-EARSM. In this thesis, Hellsten’s k − ω EARSM, which is designed for high-lift aerodynamics, is implemented to open-source CFD code flowPSI. The model is validated using seven different generic turbulence model validation and high-lift aerodynamic test cases.

Suggestions

Implementation and comparison of turbulence models on a flat plate problem using a Navier-Stokes solver
Genç, Balkan Ziya; Aksel, Mehmet Haluk; Department of Mechanical Engineering (2003)
For turbulent flow calculations, some of the well-known turbulence models in the literature are applied on a previously developed Navier-Stokes solver designed to handle laminar flows. A finite volume formulation, which is cell-based for inviscid terms and cell-vertex for viscous terms, is used for numerical discretization of the Navier-Stokes equations in conservative form. This formulation is combined with one-step, explicit time marching Lax-Wendroff numerical scheme that is second order accurate in spac...
Experimental investigation of waveform tip injection on the characteristics of the tip vortex
Ostovan, Yashar; Uzol, Oğuz; Department of Aerospace Engineering (2011)
This study investigates the effect of chordwisely modulated tip injection on the flow and turbulence characteristics of the tip vortex through experimental measurements downstream of a rectangular half-wing that has an aspect ratio of three. This injection technique involves spanwise jets at the tip that are issued from a series of holes along the chord line normal to the freestream flow direction. The injection mass flow rate from each hole is individually controlled using computer driven solenoid valves a...
Implementation and assessment of k-omega-gamma transition model for turbulent flows
Karabay, Sami; Baran, Özgür Uğraş; Department of Mechanical Engineering (2022-5-09)
The transition from laminar flow to turbulence is challenging to model in CFD. Due to the complex nature of transition, it is neglected in CFD codes usually by assuming the flow is fully turbulent. However, this results in missing the fundamental characteristics of the flow and inaccurate predictions of the flow field. Although there are several transition models, most of them cannot be used in CFD simulations due to practical issues or low accuracy. Yet, some of these models are promising and candidates to...
Detached Eddy simulation of turbulent flow on 2D hybrid grids
Yırtıcı, Özcan; Uzol, Oğuz; Tuncer, İsmail Hakkı; Department of Aerospace Engineering (2012)
In this thesis study, Detached Eddy Simulation turbulence model is studied in two dimension mainly for flow over single element airfoils in high Reynolds numbers to gain experience with model before applying it to a three dimensional simulations. For this aim, Spalart-Allmaras and standard DES ,DES97, turbulence models are implemented to parallel, viscous, hybrid grid flow solver. The flow solver ,Set2d, is written in FORTRAN language. The Navier-Stokes equations are discretized by first order accurately ce...
Applications of a 3-D numerical model to circulation in coastal waters
Balas, L; Ozhan, E (2001-06-01)
A three dimensional baroclinic numerical model which consists of hydrodynamic, transport and turbulence model components, has been applied to two test cases, including: the wind induced flow in a laboratory basin and tidal flow in a model rectangular harbor. The agreement between the physical and numerical model results is highly encouraging. Model has been implemented to Oludeniz Lagoon located at the Mediterranean coast of Turkey to simulate tidal and wind driven currents. M2 tide is the dominant tidal co...
Citation Formats
U. İlhan, “Implementation and assessment of Hellsten explicit algebraic Reynolds stress k-omega model,” M.S. - Master of Science, Middle East Technical University, 2022.