Abstract
A majority of the eddy viscosity models for supersonic turbulent flow are based on linear relationship between Reynolds stresses and mean strain rate. The validity of these models can be improved by introducing non-linearity in relation as RANS models offer advantages in terms of reduced turnaround times typical of industry applications. With these benefits, the present work utilizes quadratic constitutive relation (QCR) with Menter’s k omega SST model to characterize the flowfield of rectangular jets. The sensitivity of this model with QCR, weighted towards diffusion, dissipation, and a combination of both, is addressed. Viscous large eddy simulations (LES) with WALE subgrid scale models are employed for qualitative comparisons using a commercial solver. Massively parallel LES are enabled by the new in-house 1088-core computing cluster at the University of Cincinnati and are also used for benchmarking. The nearfield results are validated with available experimental data and show good agreement in both fidelities. Flow characteristics, including the shear layer profiles, Reynolds stresses, and turbulence kinetic energy (TKE) and its production are compared. LES reveal higher TKE production in the regions with highest Reynolds stresses. It is comparatively lower in QCR RANS. As a special case of TKE analysis in jets, a preliminary investigation of retropropulsion is outlined for rectangular nozzles for the first time. Improved flow behavior by implementation of a non-linear relationship between Reynolds stresses and mean strain rate is demonstrated.
Highlights
Turbulence is the most fascinating yet complex phenomenon that we encounter in our daily interaction with different types of fluids
The results are mainly focused on turbulent flow characterization, and the final section brieflTyhdeersecsruibltessatrheemreatirnolpyrofopcuulsseiodnoflnotwurpbhuylesnictsf.low characterization, and the final section briefly describes the retropropulsion flow physics
Non-linear eddy viscosity relation is employed in RANS and large eddy simulations (LES) to characterize the turbulent flow in supersonic rectangular jets using a commercial solver
Summary
Turbulence is the most fascinating yet complex phenomenon that we encounter in our daily interaction with different types of fluids. While Chen et al [25,26] demonstrated the vorticity dynamics-based flow diagnosis for a 1.5 stage high-pressure compressor using RANS simulations to improve compressor aerodynamic performance, Wu and Porté-Agel [27] presented the atmospheric turbulence effects on wind turbine wakes using LES. While these studies employed LES, Siddappaji [28] demonstrated TKE is equal to viscous dissipation using momentum, vorticity, and entropy transport through RANS simulations in adiabatic process with an in-house analysis framework These references provided some background on turbulence characterization for various applications, the same has not yet been shown for rectangular jets using such models. The quantities of interest were automatically extracted after a certain number of time steps after the completion of ~2–3 flowthrough times to ensure the accuracy without effects from precursor simulation
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