On November 6, 2024, we had the pleasure of hosting a seminar led by Professor Lian-Ping Wang from the Southern University of Science and Technology. The topic was “Turbulence Modulation by Suspended Finite-Size Solid Particles: DNS and Theoretical Modeling.”
Professor Wang’s presentation focused on how the presence of a dispersed phase significantly modifies small-scale fluid turbulence, an area that has not yet been comprehensively understood. The seminar was divided into two main parts:
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Interface-Resolved Simulation Results: Professor Wang discussed the results related to turbulence modulation by suspended finite-sized solid particles. He presented insights from direct numerical simulations (DNS) that highlight the interactions between turbulence and dispersed particles, emphasizing the implications for cloud microphysics and how these processes affect cloud formation and behavior. He also covered the application of the lattice Boltzmann equation, which serves as an effective tool for simulating these complex interactions.
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Physics-Based Modeling of Turbulence Modulation: The second part of the talk introduced a physics-based model for predicting turbulence modulation, specifically focusing on the modulation of turbulent kinetic energy by dispersed particles. This model is formulated from an energy flux balance equation at the inertial-subrange scale, incorporating five critical governing parameters:
- Ratio of particle size to Kolmogorov length
- Particle-to-fluid density ratio
- Particle volume fraction
- Relative mean slip velocity
- Local flow Reynolds number
Professor Wang compared the model predictions with results from particle-resolved simulations and high-fidelity experiments, discussing its capabilities in explaining both the augmentation and attenuation of turbulence, as well as the decay rate of turbulent kinetic energy.
The seminar attracted over 25 participants, both on site and online.
We thank Professor Wang for his insightful presentation and for sharing his expertise with us.