scholarly journals Non-Linear Growth of One-Dimensional Cosmological Density Fluctuation and Catastrophe Theory

1989 ◽  
Vol 81 (3) ◽  
pp. 633-647 ◽  
Author(s):  
N. Gouda ◽  
T. Nakamura
Keyword(s):  
Catastrophe Theory ◽  
Density Fluctuation ◽  
Linear Growth ◽  
One Dimensional ◽  
Non Linear

scholarly journals Interaction of equivalence ratio fluctuations and flow fluctuations in acoustically forced swirl flames

2021 ◽  
pp. 175682772110155
Author(s):  
Vincent Kather ◽  
Finn Lückoff ◽  
Christian O. Paschereit ◽  
Kilian Oberleithner
Keyword(s):  
Equivalence Ratio ◽  
Transfer Functions ◽  
Transport Model ◽  
Mode Conversion ◽  
Fuel Injector ◽  
One Dimensional ◽  
Flow Fluctuations ◽  
Non Linear ◽  
Non Local ◽  
Acoustic Forcing

The generation and turbulent transport of temporal equivalence ratio fluctuations in a swirl combustor are experimentally investigated and compared to a one-dimensional transport model. These fluctuations are generated by acoustic perturbations at the fuel injector and play a crucial role in the feedback loop leading to thermoacoustic instabilities. The focus of this investigation lies on the interplay between fuel fluctuations and coherent vortical structures that are both affected by the acoustic forcing. To this end, optical diagnostics are applied inside the mixing duct and in the combustion chamber, housing a turbulent swirl flame. The flame was acoustically perturbed to obtain phase-averaged spatially resolved flow and equivalence ratio fluctuations, which allow the determination of flux-based local and global mixing transfer functions. Measurements show that the mode-conversion model that predicts the generation of equivalence ratio fluctuations at the injector holds for linear acoustic forcing amplitudes, but it fails for non-linear amplitudes. The global (radially integrated) transport of fuel fluctuations from the injector to the flame is reasonably well approximated by a one-dimensional transport model with an effective diffusivity that accounts for turbulent diffusion and dispersion. This approach however, fails to recover critical details of the mixing transfer function, which is caused by non-local interaction of flow and fuel fluctuations. This effect becomes even more pronounced for non-linear forcing amplitudes where strong coherent fluctuations induce a non-trivial frequency dependence of the mixing process. The mechanisms resolved in this study suggest that non-local interference of fuel fluctuations and coherent flow fluctuations is significant for the transport of global equivalence ratio fluctuations at linear acoustic amplitudes and crucial for non-linear amplitudes. To improve future predictions and facilitate a satisfactory modelling, a non-local, two-dimensional approach is necessary.

Internal GIG Ecosystem in IT/ITeS Organisations for Non-linear Growth

2021 ◽  
pp. 232209372110132
Author(s):  
Debolina Dutta ◽  
Prem Mirchandani ◽  
K. P. Anasha
Keyword(s):  
Employee Satisfaction ◽  
Linear Growth ◽  
Growth Models ◽  
Global Scale ◽  
Growth Trajectory ◽  
It Services ◽  
Industry Growth ◽  
It Service ◽  
Significant Contributor ◽  
Non Linear

The Indian IT/ITeS industry is a significant contributor to India’s GDP and has had an impressive growth trajectory. However, it continues to be plagued with talent shortages, managing employee satisfaction, growth aspirations and reducing attrition. COVID-19 has presented an unprecedented opportunity for IT service organisations to transform the established paradigm of working. The industry has been exploring non-linear growth models that address the talent demand-supply gap. With skilled talent shortage continuing to limit the industry growth, non-linear initiatives of growth are urgently required. We propose a model of ‘Internal Gig’ worker (I-GIG) for the IT services industry. The new I-GIG workforce would be providing non-linear outcomes without increasing costs significantly. We also argue that this model would be motivational for employees who opt for it, with commensurate reward motivations to engage them. Additionally, this model would enable the workanywhere, anytime and leverage talent availability on a global scale.

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