Lean blowoff behavior of asymmetrically-fueled bluff body-stabilized flames

Spatio-temporal linear stability analysis of stratified planar wakes: Velocity and density asymmetry effects

“…Previous stability analyses have elucidated the influence that S and λ have on the flow stability. 25,30 As such, this section focuses on the influence of the asymmetry parameters on the flow stability, which may be compared to the experimental results of Tuttle et al 29 It is important to note that this section presents quantitative stability predictions (frequencies, growth rates, critical parameters for absolute/convective transition, etc.) in the context of the base flow model, which describes a reduced set of stability parameters.…”

“…This section presents experimental data obtained by Tuttle et al, 29 which was described in Section I. The end of this section compares the available experimental results to the stability analysis to demonstrate some of the predicted parametric dependencies.…”

“…Their data show that a narrowband feature in the chemiluminescence spectrum appears and increases in amplitude with increases in level of equivalence ratio stratification. 29 Interpreted in the light of the above hydrodynamic stability discussion, this result suggests that wake density asymmetry promotes global instability. The objective of this study is to parameterize base flow asymmetry parameters upon the hydrodynamic stability trends of the flow.…”

“…The majority of existing analyses and experiments have focused on symmetric configurations (symmetric geometry and time-averaged flow). 20,21,27,28 A notable exception is the recent experiments by Tuttle et al, 29 who analyzed the dynamics of combusting wakes which were fueled with varying degrees of transverse stratification with respect to the bluff body centerline. Figure 2(a) shows their stratified equivalence ratio profile, where the nominal equivalence ratio, φ, varies between φ − φ ε and φ + φ ε at y = H and y = −H, respectively.…”

“…The objective of this study is to parameterize base flow asymmetry parameters upon the hydrodynamic stability trends of the flow. The model is also compared to experimental data of Tuttle et al 29 to assess its ability to capture the key qualitative effects of these base flow asymmetry parameters.…”