An LES Turbulent Inflow Generator using A Recycling and Rescaling Method

Area of Science:

• Computational Fluid Dynamics (CFD)
• Turbulence Modeling
• Fluid Mechanics

Background:

• Accurate simulation of turbulent flows requires realistic inflow conditions.
• Traditional methods often struggle to generate self-consistent turbulence structures.
• Large Eddy Simulation (LES) is sensitive to inlet turbulence characteristics.

Purpose of the Study:

• To present and validate a novel recycling and rescaling method for generating turbulent inflow conditions.
• To demonstrate the method's capability in producing realistic and self-consistent turbulence.
• To assess the method's applicability to complex industrial flow scenarios and multiphase flows.

Main Methods:

• A recycling and rescaling algorithm is employed to generate inflow turbulence.
• The method requires only mean velocities and turbulence root-mean-square (rms) levels as input.
• Validation is performed through simulations of turbulent boundary layers, mixing layers, and droplet-laden mixing layers.

Main Results:

• The method successfully generates realistic turbulence structures, including 1-point and 2-point correlations not explicitly provided.
• Simulations show accurate prediction of growth rates for boundary and mixing layers.
• The approach effectively handles complex inflows like non-equilibrium and spanwise inhomogeneous turbulence, and accurately reproduces droplet dispersion.

Conclusions:

• The recycling and rescaling method provides a robust and versatile approach for generating high-fidelity turbulent inflow conditions for LES.
• The method enhances the accuracy of simulations for fundamental turbulent flows and complex industrial applications.
• Accurate reproduction of turbulence structures leads to improved predictions of phenomena like droplet dispersion.