Synthetic turbulence to achieve swift converged turbulence statistics in a pressure-driven channel flows

In this study, we introduced a simple yet innovative application of the synthetic eddy method, the isotropic synthetic turbulence field generator (iSTFG) that leverages the homogeneity in the streamwise direction for channel flows, and triggers turbulence to achieve statistically stationary flow conditions faster than current standard community-used strategies. We compare this new method with two other well-established methods: linear profile superposed with random noise and descending counter-rotating vortices and log-law profile superposed with random noise and descending counter-rotating vortices. We found that iSTFG provides a computationally cheap and effective way to reduce simulation spin-up costs/time/emissions to achieve statistically stationary flow conditions when a precursor turbulent initial condition is unavailable. At a one-time cost between 1-10 Cental Processing Unit (CPU) hour(s) to generate the synthetic turbulent initial condition based on the target friction Reynolds numbers (1 CPU hour - Re = 500, 7 CPU hours - Re = 2000), the flow becomes statistically stationary within three eddy turnovers for all the parameters of interest in wall-bounded pressure-driven channel flow simulations when compared to other alternatives that can take more than ten eddy turnovers resulting in substantial savings in the computational cost. This method offers a practical and efficient solution for researchers studying turbulent channel flows, enabling faster convergence to a statistically stationary flow state.

Recommended citation: Patil, A. and C. García-Sánchez, (in review, Physics of Fluids), (2025), Synthetic turbulence to achieve swift converged turbulence statistics in a pressure-driven channel flows
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