Evaluation of Modified Two-Equation Turbulence Models for Jet Flow Predictions

The Effects of Surfaces on the Aerodynamics and Acoustics of Jet Flows

“…Furthermore, the predicted magnitude of peak TKE is lower than measurement. However, the global qualitative agreement is favorable compared to other solutions produced by similar CFD codes (for example see Georgiadis et al 25 ). Qualitative comparisons are conducted for the isolated jet by examining aerodynamic data along the centerline and axial locations at x/D = 1, 4, and 16.…”

Unsteady Predictions of Mixing Enhancement with Steady and Pulsed Control Jets

“…This is a well-known flaw in eddy viscosity-based RANS turbulence models when applied to the analysis of propulsive jet near-field mixing. This topic has been extensively reviewed by Georgiadis et al [23], and Georgiadis and DeBonis [24]. Their main conclusions were: (i) standard two-equation models (with model constants calibrated against a wide range of 2D shear flows to give optimum overall accuracy) consistently overpredicted round jet potential core length due to inhibited initial turbulence growth rate and produced a too rapid initial centreline decay rate relative to experimental data, (ii) several attempts to introduce modifications and corrections to improve accuracy for near-field jet mixing were shown to have rather variable results.…”

“…The rest of the paper describes the application and validation of URANS for the Mach 0.9 cold jets studied experimentally by Kamran and McGuirk [2] and Kamran [14] for baseline (unexcited), steady, and pulsed CJ excitation. Given that no firm recommendation on k-ε model improvements was made in [23], [24], the standard model was employed in the predictions shown below.…”

Frozen Chemistry Effects on Nozzle Performance Simulations

“…The domain extends 40 diameters downstream and 25 diameters in the radial direction. In a previous study 9 involving Wind, grid independence was demonstrated through grid sequencing. Thus a new grid independence study was not undertaken.…”

“…[8][9][10] Those studies have largely focused on the effects of turbulence models on the decay of jet plumes where the exhaust gas was modeled using air and treated as calorically perfect. For the current series of calculations, Menter's Shear Stress Transport (SST) turbulence model 11 was used with P r t = 0.70 and three different gas models.…”