Sensitivity analysis of initial condition parameters on the transitional temporal turbulent mixing layer

Fathali, Mani; Meyers, Johan; Rubio, Gustavo; Smirnov, Sergey; Baelmans, Martine

doi:10.1080/14685240801964912

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…In contrast, the flow field is dominated by more regular and smooth streamwise elongated vortices at M c = 1.8 and τ = 250. This phenomenon is consistent with previous studies of small-scale vortical structures in compressible mixing layer, where it is generally believed that the vortical structures are more aligned in the streamwise direction at higher M c , particularly in the transition region (Balaras et al 2001;Fathali et al 2008;Arun et al 2019;Li et al 2021).…”

Section: φ =supporting

confidence: 92%

“…2001; Rossmann, Mungal & Hanson 2002; Fathali et al. 2008; Hickey, Hussain & Wu 2016; Arun et al. 2019; Li et al.…”

Section: Introductionmentioning

confidence: 99%

“…In incompressible and weakly compressible mixing shear layers, the flow is dominated by large, predominantly two-dimensional, spanwise vortex structures (rollers) and rib-like vortices that arise from the Kelvin-Helmholtz instability of the layer (Rogers & Moser 1994;Balaras, Piomelli & Wallace 2001;Wang, Tanahashi & Miyauchi 2007). As the mixing layer becomes more compressible, the large roller structures break down and the vortical structures are greatly stretched in the streamwise direction, which leads to different mixing characteristics (Sandham & Reynolds 1991;Balaras et al 2001;Rossmann, Mungal & Hanson 2002;Fathali et al 2008;Hickey, Hussain & Wu 2016;Arun et al 2019;Li et al 2021). In DNSs of spatially evolving mixing layers by Zhou, He & Shen (2012), it was observed that Λ structures in the flow field evolve to hairpin vortices which eventually break down to slender vortices before the flow reaches a self-similar state.…”

Section: Introductionmentioning

confidence: 99%

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Compressibility effects on statistics and coherent structures of compressible turbulent mixing layers

Wang

Chen

2022

J. Fluid Mech.

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The effects of compressibility on the statistics and coherent structures of a temporally developing mixing layer are studied using numerical simulations at convective Mach numbers ranging from $M_c=0.2$ to $1.8$ and at Taylor Reynolds numbers up to 290. As the convective Mach number increases, the streamwise dissipation becomes more effective to suppress the turbulent kinetic energy. At $M_c=1.8$ , the streamwise dissipation increases much faster than the other two components in the transition region, even larger than pressure–strain redistribution, correlating with the streamwise elongated vortical structures at a higher level of compressibility. We confirm the existence of the large-scale high- and low-speed structures in the mixing layers, which accompany the spanwise Kelvin–Helmholtz rollers at low convective Mach number and dominate the mixing layer at higher convective Mach number. Conditional statistics demonstrate that the large-scale low-speed structures are lifted upwards by a pair of counter-rotating quasi-streamwise rollers flanking the structures. The small-scale vortical structures have an apparent preference for clustering into the top of the low-speed regions, which is directly associated with high-shearing motions on top of the low-speed structures. The high-speed structures statistically exhibit central symmetry with the low-speed structures. The statistics and dynamics of large-scale high- and low-speed structures in the compressible mixing layers resemble those in the outer region of the turbulent boundary layers, which reveals the universality of the large-scale structures in free shear and wall-bounded turbulence. A conceptual model is introduced for the large-scale high- and low-speed structures in turbulent mixing layers.

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Section: φ =supporting

confidence: 92%

“…2001; Rossmann, Mungal & Hanson 2002; Fathali et al. 2008; Hickey, Hussain & Wu 2016; Arun et al. 2019; Li et al.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Compressibility effects on statistics and coherent structures of compressible turbulent mixing layers

Wang

Chen

2022

J. Fluid Mech.

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“…This is appropriate because the velocity field drives the instability and turbulence, as observed in the single-density case; this approach also allows the disturbance to be consistent between Atwood numbers. Different velocity disturbances can produce significantly different growth rates at early times in mixing layers (Fathali et al 2008), but the present goal is to quickly establish self-similar growth and minimize long-lived large-scale structures that are uniquely associated with initial disturbances. To roughly resemble physical experiments, the velocity perturbation is confined to a thin (in y) region centred at the mean velocity profile interface.…”

Section: Initial Disturbancementioning

confidence: 99%

Variable-density effects in incompressible non-buoyant shear-driven turbulent mixing layers

Baltzer

Livescu

2020

J. Fluid Mech.

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“…The first method utilizes a stochastic approach whereby the "turbulent" perturbations are comprised from random realizations having statistical equivalency to that of the actual turbulent flow field. 34,[41][42][43] The second method uses the output from DNS and Large Eddy Simulations ͑LES͒ that have been performed separately on an extended computational domain encompassing the splitter plate. [44][45][46] The third least expensive and simplest method of initiating the turbulence follows from linear stability theory.…”

Section: Problem Definitionmentioning

confidence: 99%

Coherent features in the sensitivity field of a planar mixing layer

Zayernouri

Metzger

2011

Physics of Fluids

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Coherency in the topology of the instantaneous sensitivity fields of the planar mixing layer was captured using the sensitivity equation method ͑SEM͒. In the SEM approach, the partial differential equations governing the evolution of the sensitivity coefficients are derived, discretized, and solved directly, in the present work, using an unsteady finite-volume-based fractional-step algorithm. This allows the investigation of parameter-dependence without performing parametric studies. The present results, from numerical simulations run at Re ␦ 0 = 200 and Pr= 0.71, provide a means to examine how and to what extent perturbations in the Reynolds/Prandtl number locally alter the structure of the flow. Specifically, a two-blade pattern appears as a dominant feature in the sensitivity solution and highlights the physical mechanism leading to vortex thickness growth and enhanced molecular mixing with increasing Re ␦ 0 and Pr. An expression describing the sensitivity of vortex thickness to changes in Re ␦ 0 is also derived and validated using the concept of "nearby" flows.

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Sensitivity analysis of initial condition parameters on the transitional temporal turbulent mixing layer

Cited by 6 publications

References 30 publications

Compressibility effects on statistics and coherent structures of compressible turbulent mixing layers

Compressibility effects on statistics and coherent structures of compressible turbulent mixing layers

Variable-density effects in incompressible non-buoyant shear-driven turbulent mixing layers

Coherent features in the sensitivity field of a planar mixing layer

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