Synthetic turbulence generation for high-order scale-resolving simulations on unstructured grids

Abstract

An extended version of the synthetic eddy method for generation of synthetic turbulence has been developed via a source term formulation and implemented in the open-source cross-platform solver PyFR. The method caters for the full space-dependent anisotropy of the target turbulent length scales, and it is agnostic of the space and time discretization of the underlying solver, which can be incompressible or compressible. Moreover, the method does not require each solution point to communicate with nearest neighbors; thus, it is well suited for modern, massively parallel, high-order unstructured codes which support mixed and possibly curved elements. The method has been applied to two test cases: incompressible plane channel flow at Reτ 180 and compressible flow over an SD7003 aerofoil at Re 66;000, Ma 0.2, and α 4 deg. The channel flow case was run on three topologically different meshes composed of hexahedra, prisms, and a combination of prisms and tetrahedra, respectively. Almost identical results have been obtained on the three meshes. Results also show that taking into account the anisotropy of the turbulent length scales can reduce the development length. For the SD7003 aerofoil case, the injection of synthetic turbulence improves agreement between numerical and experimental results.