(230av) Scalable Tools for Generating Synthetic Isotropic Turbulence with Arbitrary Spectra

A scalable, parallel, isotropic turbulence generator is developed and deployed online at http://turbulence.utah.edu (password: utahturbogen) for immediate access by the fluids, aerosapce, and aeroacoustics communities. The generated isotropic turbulence can be used for a priori and a posteriori verification and validation of turbulence codes and models as well as aeroacoustics calculations. This synthetic generator takes an arbitrary energy spectrum as input and produces a velocity field that matches the given spectrum up to the Nyquist limit. The Nyquist limit is dictated by the domain size and grid resolution, which are specified by the user. The velocity field is stored on a staggered grid and satisfies the discrete divergence-free requirement on the vast majority of grid points without the need for a mass correction procedure. The turbulence generator was conveniently coded in Python, C, and C++ using parallel computing concepts and is freely available to execute online in a web browser. The errors produced by the generator are examined for canonical spectra, such as the Comte-Bellot-Corrsin and the von Karman-Pao spectra. The scalability of the codes are verified and compared for various grid resolutions. Finally, an example application is presented for decaying isotropic turbulence.