URANS simulations of separated flow with stall cells over an NREL S826 airfoil

Sarlak, Hamid; Nishino, Takafumi; Sørensen, Jens Nørkær

doi:10.1063/1.4951795

Cited by 6 publications

(4 citation statements)

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“…Experimental measurements have shown the existence of coherent structures commonly referred to as stall cells, characterized by oil flow and tuft measurements in the shape of counterrotating swirl patterns, poetically addressed as owl faces or mushroom cells [84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101]. These features also have been predicted numerically [102,103,90,91,104]. A more theoretical description can be given by means of critical point theory 7 : stall cells can be recognized on the surface as two foci connected by two separation lines emerging from a saddle point [102] (Figure 3).…”

Section: Stall Characteristics and Stall Cellsmentioning

confidence: 73%

“…Werlé [112] and hypothesized by Legendre [113] in the 1960s at which time they referred to the dividing surface as being of the "horn-type". In The appearance of stall cells has also been shown by means of RANS simulations through studies by Sarlak et al [103] using the k − ω SST model [11] on a NACA 0012 profile at Re c = 0.39 [65]. Increasing T u diminishes this effect [136].…”

Section: Stall Characteristics and Stall Cellsmentioning

confidence: 83%

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On the study of transitional low-Reynolds number flows over airfoils operating at high angles of attack and their prediction using transitional turbulence models

Wauters

Degroote

2018

Progress in Aerospace Sciences

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In this survey paper transitional turbulence modeling is approached from the point of view relevant to small unmanned aerial vehicles (span ≈ 1m), of which the flow is characterized by very low values of turbulent intensity and transition is predominantly of the separation induced kind. The physical mechanisms that are present during transition are discussed based on the experimental and numerical findings of the last five decades and their influence on high angle of attack behavior, with the appearance of abrupt stall, stall cells, low frequency oscillations and hysteresis are reviewed. Furthermore, an overview will be given of the different methodologies that exist to predict transitional flows. Emphasis will be placed on the modeling of separation bubbles within the RANS-based environment: a number of transitional turbulence models will be summarized and categorized based on their transition predicting methodologies. Four different turbulence models for low Reynolds number flow will be discussed in depth: Menter's k − ω SST model with Wilcox's low-Re modification, Menter & Langtry's (k − ω SST) γ − Re θ model, it's simplified (k − ω SST) γ model and Walters & Cokljat's k − k l − ω model.

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Section: Stall Characteristics and Stall Cellsmentioning

confidence: 73%

Section: Stall Characteristics and Stall Cellsmentioning

confidence: 83%

On the study of transitional low-Reynolds number flows over airfoils operating at high angles of attack and their prediction using transitional turbulence models

Wauters

Degroote

2018

Progress in Aerospace Sciences

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“…A standard k − formulation is used to model the turbulence for the cases at Re = 10 6 and 7 • 10 6 . For the subcritical case at Re = 10 5 a k − ω SST model is used for its performance and its low sensitivity to the initial conditions following Sarlak et al [25]. Crank-Nicolson time discretization is used for the temporal derivatives and the gradient, Laplacian and divergence terms are solved using Gauss linear, Gauss linear corrected, and Gauss linear discretization schemes, respectively.…”

Section: Unsteady Rans Simulationsmentioning

confidence: 99%

Simulation of the flow past a circular cylinder using an unsteady panel method

Ramos‐García

Sarlak

Andersen

et al. 2017

Applied Mathematical Modelling

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“…Aftab et al [11] investigated various turbulence models on the NACA4415 wing in the Reynolds Number of 120,000 and claimed that Spallart-Allmaras was a successful model in numerical analysis only until the stall developed, although the γ-Re SST model was successful in the entire attack angle. Sarlak et al [12], in S826 airfoils, at 40,000, 100,000 and 200,000 Reynolds numbers applied the SST k-ω model and found that the SST k-model can predict 3D flow structures. Ahmed et al [13] conducted an experimental and numerical study on SG6043 airfoils at Reynolds numbers ranging from 38,000 to 200,000, with turbulence levels ranging from 1%, 5% and 10%.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of NACA 6409 and Eppler 423 Airfoils

Durmuş¹,

Ulutaş²

2023

Politeknik Dergisi

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 Current paper focuses on RANS based turbulence analysis of NACA 6409 and Eppler 423.  θ-Reθ SST was the RANS model that gave the most consistent results with the experimental data.  CFD Simulation results of pressure and velocity fields at different angles of attack are clearly presented.  CFD results with experimental data and XFoil are evaluated in terms of best glide ratio-(Cl/Cd)max and minimum sink-(Cl 1.5 /Cd)max criteria.

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URANS simulations of separated flow with stall cells over an NREL S826 airfoil

Cited by 6 publications

References 7 publications

On the study of transitional low-Reynolds number flows over airfoils operating at high angles of attack and their prediction using transitional turbulence models

On the study of transitional low-Reynolds number flows over airfoils operating at high angles of attack and their prediction using transitional turbulence models

Simulation of the flow past a circular cylinder using an unsteady panel method

Numerical Analysis of NACA 6409 and Eppler 423 Airfoils

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