Comparative study of spectral-element and finite-volume solvers for direct numerical simulation of synthetic jets

Abstract

Direct Numerical Simulations of synthetic jet flow fields issuing in a quiescent environment, performed by means of two extensively used open-source computational fluid dynamics (CFD) codes, Nek5000 and OpenFOAM solver pimpleFoam, are reported and compared. While the former employs a high-order spectral-element method, the latter is based on finite-volume, lower-order schemes. The present paper specifically refers to SJ fields produced by slotted orifice piezo-driven actuators. The dimensionless flow parameters adopted to perform the simulations basically match the experimental data of Yao et al. (2006), whilst a reasonably simplified geometry of the actuator is adopted. Results are generally in good agreement with the experimental data for both codes, in terms of first- and second-order moments of the long-time and phase-averaged velocity field, as well as of global engineering quantities. The performances of the two codes are compared thoroughly, with regard to accuracy and computer load as well. Overall, when high-fidelity of simulations is required for the problem under study, Nek5000 is found to be computationally more efficient.