An investigation of the lattice Boltzmann equation-based hybrid approach for simulation of sound generated by isotropic turbulence

• Noise radiated by forced isotropic turbulence is studied using a hybrid lattice Boltzmann model-based DNS/acoustic analogy.
• A deterministic forcing model is implemented in LBM and its characteristics are compared to a stochastic scheme.
• The acoustical spectrum and sound pressure level are first evaluated with the hybrid method.
• The effect of local time delay on noise prediction is addressed when Lighthill’s analogy and LBM/DNS are combined.

We study noise radiated by forced isotropic turbulence numerically using a hybrid approach, i.e. lattice Boltzmann equation-based DNS/acoustic analogy. In the present contribution, a deterministic force model is developed in direct LBM simulations and its characteristics is analyzed and compared to a recently proposed stochastic forcing scheme. The fluctuating acoustic pressure, acoustical spectrum and sound pressure level are first evaluated on the ground of the hybrid approach and compared with the results from various numerical and analytical solutions. In this paper, we also address the effects of local time delay based on different forcing schemes on prediction of the radiated noise when Lighthill’s acoustic analogy and LBM are used for computation of the turbulent flow field and acoustic field.