Computational Singular Perturbation Method and Tangential Stretching Rate Analysis of Large Scale Simulations of Reactive Flows: Feature Tracking, Time Scale Characterization, and Cause/Effect Identification. Part 1, Basic Concepts

Valorani, Mauro; Creta, Francesco; Ciottoli, Pietro Paolo; Galassi, Riccardo Malpica; Goussis, Dimitris A.; Najm, Habib N.; Paolucci, Samuel; Im, Hong G.; Tingas, Efstathios-Al.; Manias, Dimitris M.; Parente, Alessandro; Li, Z.; Grenga, Temistocle

doi:10.1007/978-3-030-44718-2_3

Cited by 12 publications

(9 citation statements)

References 35 publications

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“…These tools have been already tested successfully in a wide range of different applications in reacting flows. Here only brief descriptions of the mathematical tools will be provided, but for a detailed analysis of the CSP framework and the developed tools, the reader is referred to Refs [125][126][127][128]. In the CSP framework, the vector field of the original system of species mass fractions and temperature ordinary differential equations (ODEs) is decomposed into components, typically called modes.…”

Section: Methodsmentioning

confidence: 99%

The chemical dynamics of hydrogen/hydrogen peroxide blends diluted with steam at compression ignition relevant conditions

Tingas

2021

Fuel

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Section: Methodsmentioning

confidence: 99%

The chemical dynamics of hydrogen/hydrogen peroxide blends diluted with steam at compression ignition relevant conditions

Tingas

2021

Fuel

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“…which quantify how a process influences the variation of a state variable in the slow and fast subspaces [29]. In addition, the driving time scale of the droplet is estimated by the tangential stretching rate (TSR) [38,39]. Given two nearby trajectories x 1 and x 2 = x 1 + ε ε ε in the state space, where ε ε ε is a small (vector) perturbation, a scaled distance between the two trajectories v in the tangent space T x0 is defined as:…”

Section: Csp Applied To Droplet Dynamicsmentioning

confidence: 99%

Analysis of droplet evaporation dynamics using computational singular perturbation and tangential stretching rate

Angelilli,

Galassi,

Ciottoli

et al. 2024

Preprint

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Computational singular perturbation (CSP) has been successfully used in the analysis of complex chemically reacting flows by systematically identifying the intrinsic timescales and slow invariant manifolds that capture the essential subprocesses driving the dynamics of the system. In this article, the analytical and computational framework is applied for the first time to analyze the Lagrangian droplets undergoing evaporation and dispersion in the surrounding gases. First, a rigorous mathematical formulation is derived to adapt the CSP tools into the droplet dynamics equations, including the formal definition of the tangential stretching rate (TSR) that represents the explosive/dissipative nature of the system. A steady ammonia and a falling water droplet studies are then conducted to demonstrate the utility of the CSP methodology in identifying various physical mechanisms driving the evolution of the system, such as the distinction of thermal-driven and mass-driven regimes. Various definitions of the importance indices are also examined to provide in-depth analysis of different subprocesses and their interactions in modifying the droplet dynamics.

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“…The details of the CSP method used herein and its algorithmic tools have been discussed elsewhere (see for instance [83][84][85][86][87]), and only a brief summary is provided here. Consider the system of species and temperature equations in the general form of…”

Section: Computational Singular Perturbation (Csp) and Its Algorithmi...mentioning

confidence: 99%

Asymptotic Analysis of Detonation Development at SI Engine Conditions Using Computational Singular Perturbation

Dimitrova¹,

Sanal²,

Luong³

et al. 2022

Preprint

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The occurrence and intensity of the detonation phenomenon at spark-ignition (SI) engine conditions is investigated, with the objective to successfully predict super-knock and to elucidate the effect of kinetics and transport at the ignition front. The computational singular perturbation (CSP) framework is employed in order to investigate the chemical and transport mechanisms of deflagration and detonation cases in the context of 2D high-fidelity numerical simulations. The analysis revealed that the detonation development is characterized by: (i) stronger explosive dynamics and (ii) enhanced role of convection. The role of chemistry was also found to be pivotal to the detonation development which explained the stronger explosive character of the system, the latter being an indication of the system's reactivity. The role of convection was found to be enhanced at the edge of the detonating front, thereby suggesting that it is the result and not the cause of the detonation onset. Moreover, the increased contribution of convection was found to be related mainly to heat convection. Remarkably, the detonation front was mainly characterized by dissipative and not explosive dynamics. Finally, diffusion was found to have negligible role to both examined cases.

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Computational Singular Perturbation Method and Tangential Stretching Rate Analysis of Large Scale Simulations of Reactive Flows: Feature Tracking, Time Scale Characterization, and Cause/Effect Identification. Part 1, Basic Concepts

Cited by 12 publications

References 35 publications

The chemical dynamics of hydrogen/hydrogen peroxide blends diluted with steam at compression ignition relevant conditions

The chemical dynamics of hydrogen/hydrogen peroxide blends diluted with steam at compression ignition relevant conditions

Analysis of droplet evaporation dynamics using computational singular perturbation and tangential stretching rate

Asymptotic Analysis of Detonation Development at SI Engine Conditions Using Computational Singular Perturbation

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