Simulations of Incompressible Separated Turbulent Flows around Two-Dimensional Bodies with URANS Models in OpenFOAM

Abstract

The goal of this study is to determine whether an unsteady formulation of a RANS turbulence model leads to improved description of incompressible separated turbulent flows around two-dimensional bodies. Two geometries are considered: a NACA 4412 airfoil and a circular cylinder. Simulations are conducted with two-equation turbulent models: Menter's 1994 Shear Stress Transport model and Wilcox's 2006 -model, implemented in the opensource CFD OpenFOAM software. Comparison with experimental data and computational results obtained from Large and Detached Eddy Simulations as well as with URANS/RANS models by other research groups is also provided. Nomenclature Re = Reynolds number, U ∞ ρ/ v M = Mach number, U ∞ /a ρ = density P = pressure a = speed of sound U ∞ = free stream velocity u = streamwise velocity component = vertical velocity component u' = velocity fluctuation in the streamwise direction I = turbulence intensity, v = kinematic viscosity  = dynamic viscosity c = chord C p = pressure coefficient, C pb = base pressure coefficient at C D = drag coefficient, C L = lift coefficient, C f = friction coefficient, A = frontal area F D = drag force 1 Graduate Student, Mechanical Engineering, MSC01 1105, 1 UNM Albuquerque, NM, 87131-00011, AIAA Student Member. 2 F L = lift force D = diameter = wall shear stress = friction velocity, x = streamwise flow direction y = normal-to-wall direction y + = dimensionless distance from the wall based on fluid properties, y w = distance between a wall and the first grid node in the y-direction t = time t* = dimensionless time = azimuth angle measured clockwise from the stagnation point = separation angle measured clockwise from the stagnation point α = angle of attack ω = turbulent specific dissipation, ε/ k ε = turbulent scalar dissipation k = turbulent kinetic energy = blending constant, L R = recirculation length h = characteristic mesh length for the constant domain size, N = total number of nodes in the computational domain

Numerical Investigation of Flow around Two Tandem Cylinders in the Upper Transition Reynolds Number Regime Using Modal Analysis

“…However, the present predicted values were close to those reported by Porteous et al (2015) [33] and Pang et al (2016). The value of St was higher than the value predicted by Porteous et al (2015) [33] but close to the data reported by Ong et al (2009), Pang et al (2016) [34] and Janocha et al ( 2021) [35]. To sum up, a general agreement with the published data could be achieved by the present numerical model.…”

“…However, the C L,rms , which was more sensitive than the value of C D , was different from the obtained value of C L,rms reported by Ong et al (2009) [2], where the k − ε turbulence model was applied. However, the present predicted values were close to those reported by Porteous et al (2015) [33] and Pang et al (2016). The value of St was higher than the value predicted by Porteous et al (2015) [33] but close to the data reported by Ong et al (2009), Pang et al (2016) [34] and Janocha et al ( 2021) [35].…”