Nek5000 ResolventTools is intended as a collection of resolvent-based tools developed on top of Nek5000 code, which can be used for resolvent analysis [1], estimation and control [2,3] of incompressible flows.
The tools used here share a set of routines, e.g. for reading/saving snapshots, computing Fourier transforms, etc. These are stores in the "Libs" folder. Links for the routines used are created on each tool folder using the importLibs file on each subfolder.
Time marching and other intensive tasks are implemented on top of Nek5000 open-source code, with most pos/pre processing operations are performed in the Octave/Matlab environment, please make sure to have these setup and working. The tools were developed and tested using v17, but should also work with v19.
To download the code Nek5000 Resolvent tools use this link, for a clean version of the code, this link to also obtain files needed to run the exaples, or by the terminal by typing:
git clone https://github.com/eduardomartini/Nek5000_ResolventTools.git.
For flexibility, all the tools are developed as to use Nek5000 for intensive tasks, e.g. time integration, application of time filters, some Fourier transforms, etc. Less intensive tasks are performed using Octave/Matlab. For computation of Resolvent modes Octave is preferred, as the code typically has a shorter initialisation time. For the control module Matlab was seen to provide a slightly faster computational times
Specific instructions for each tools are included in their respective folders.
In all the tools provided here, direct and adjoint solvers are used. In its current state, the code assumes that the boundary conditions for both problems are the same, e.g., Dirichlet boundary conditions. If this is not the case for your problem, adapt the code accordingly, e.g., changing the b.c. in the .rea file before each run, or setting the appropriate b.c. in the .usr file.
- Martini, Eduardo, Daniel Rodríguez, Aaron Towne, and André V. G. Cavalieri. “Efficient Computation of Global Resolvent Modes,” Journal of Fluid Mechanics 919 (2021): A3. https://doi.org/10.1017/jfm.2021.364
- Journal of Fluid Mechanics, 919, A3. Cambridge Core.
- Martini, Eduardo, André V. G. Cavalieri, Peter Jordan, Aaron Towne, and Lutz Lesshafft. “Resolvent-Based Optimal Estimation of Transitional and Turbulent Flows.” Journal of Fluid Mechanics 900 (2020): A2. https://doi.org/10.1017/jfm.2020.435
- E. Martini, J. Jung , A. V. G. Cavalieri, P. Jordan, L. Lesshafft & A. Towne, Optimal causal Resolvent-based control using the Wiener-Hopf formalism. Journal of Fluid Mechanics, (2021) [submitted]
Martini, E., Rodríguez, D., Towne, A., & Cavalieri, A. V. G. (2021). Efficient computation of global resolvent modes. Journal of Fluid Mechanics, 919, A3. Cambridge Core. https://doi.org/10.1017/jfm.2021.364