Abstract
The first fractional model for Reynolds stresses in wall-bounded turbulent flows was proposed by Wen Chen [2]. Here, we extend this formulation by allowing the fractional order α(y) of the model to vary with the distance from the wall (y) for turbulent Couette flow. Using available direct numerical simulation (DNS) data, we formulate an inverse problem for α(y) and design a physics-informed neural network (PINN) to obtain the fractional order. Surprisingly, we found a universal scaling law for α(y+), where y+ is the non-dimensional distance from the wall in wall units. Therefore, we obtain a variable-order fractional model that can be used at any Reynolds number to predict the mean velocity profile and Reynolds stresses with accuracy better than 1%.
This paper is dedicated to the memory of the late Professor Wen Chen
Acknowledgements
The work was partially supported by the MURI/ARO at Brown University (W911NF-15-1-0562) and DARPA-AIRA (HR00111990025).
References
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© 2019 Diogenes Co., Sofia
Articles in the same Issue
- Frontmatter
- Editorial Note
- FCAA special issue – In memory of late professor Wen Chen (FCAA–Volume 22–6–2019)
- Survey Paper
- State-of-art survey of fractional order modeling and estimation methods for lithium-ion batteries
- An investigation on continuous time random walk model for bedload transport
- Tutorial Survey
- Porous functions
- Research Paper
- A time-space Hausdorff derivative model for anomalous transport in porous media
- High-order algorithms for riesz derivative and their applications (IV)
- Mass-conserving tempered fractional diffusion in a bounded interval
- Dispersion analysis for wave equations with fractional Laplacian loss operators
- Lagrangian solver for vector fractional diffusion in bounded anisotropic aquifers: Development and application
- Some further results of the laplace transform for variable–order fractional difference equations
- Robust stability analysis of LTI systems with fractional degree generalized frequency variables
- Discovering a universal variable-order fractional model for turbulent Couette flow using a physics-informed neural network
Articles in the same Issue
- Frontmatter
- Editorial Note
- FCAA special issue – In memory of late professor Wen Chen (FCAA–Volume 22–6–2019)
- Survey Paper
- State-of-art survey of fractional order modeling and estimation methods for lithium-ion batteries
- An investigation on continuous time random walk model for bedload transport
- Tutorial Survey
- Porous functions
- Research Paper
- A time-space Hausdorff derivative model for anomalous transport in porous media
- High-order algorithms for riesz derivative and their applications (IV)
- Mass-conserving tempered fractional diffusion in a bounded interval
- Dispersion analysis for wave equations with fractional Laplacian loss operators
- Lagrangian solver for vector fractional diffusion in bounded anisotropic aquifers: Development and application
- Some further results of the laplace transform for variable–order fractional difference equations
- Robust stability analysis of LTI systems with fractional degree generalized frequency variables
- Discovering a universal variable-order fractional model for turbulent Couette flow using a physics-informed neural network