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Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions
Published on: February 22, 2018
Using nonlinear transient growth to construct the minimal seed for shear flow turbulence
Chris C T Pringle1, Rich R Kerswell
1Department of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK. C.C.T.Pringle@reading.ac.uk
Physical Review Letters
|January 15, 2011
Summary
Nonlinear analysis reveals more effective 3D disturbances for triggering turbulence in pipe flow, outperforming traditional 2D rolls. This finding offers improved methods for designing transition-inducing perturbations.
Area of Science:
- Fluid dynamics
- Turbulence theory
- Nonlinear dynamics
Background:
- Linear transient growth analysis is a standard method for identifying optimal disturbances that trigger turbulence in shear flows.
- Previous studies often relied on linear analysis, potentially overlooking more effective transition pathways.
Purpose of the Study:
- To investigate the impact of nonlinearity on disturbance structure and efficiency in triggering turbulence in pipe flow.
- To compare the effectiveness of nonlinear optimal disturbances against linear optimal disturbances.
Main Methods:
- Incorporation of nonlinear terms into transient growth analysis.
- Analysis of disturbance structures in pipe flow under nonlinear conditions.
- Comparison of turbulence triggering efficiency between linear and nonlinear optimal states.
Main Results:
- Nonlinear analysis predicts a shift from 2D streamwise rolls to localized 3D states.
- The identified nonlinear optimal disturbance is significantly more efficient at triggering turbulence than the linear optimal.
- This highlights the limitations of purely linear approaches in predicting optimal transition pathways.
Conclusions:
- Nonlinear effects are crucial for accurately predicting the most efficient disturbances for turbulence transition in pipe flow.
- The findings suggest novel strategies for designing perturbations to intentionally induce turbulence, with potential applications in flow control and mixing enhancement.
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