Free surface phenomena – think sloshing, vortex formation, air entrainment through water surface, or filling and draining systems – present a fascinating blend of physics and engineering, posing complex modeling challenges. However, the inherent complexities and nuances associated with free surface phenomena pose unique challenges that can lead to inaccuracies if not addressed properly. This is where transient schemes and Large Eddy Simulation (LES) come into play.
Turbulence, a ubiquitous feature of fluid flows, significantly impacts free surface dynamics. However, traditional turbulence modeling methods often fall short in accurately capturing turbulent flow structures, thereby affecting the fidelity of the simulation results. LES, as a turbulence-resolving method, provides a fine-grained understanding of turbulent flows. It works by resolving the larger, more energy-containing eddies while modeling the smaller, more universal scales. This approach significantly enhances the accuracy of turbulence predictions, especially for complex, transient flow problems where turbulence plays a key role.
With the increased accessibility and reduced computational cost brought by advancements in GPU-accelerated simulations, such as with M-STAR CFD, LES is no longer confined to high-end research but is steadily transforming everyday engineering practices. As an example, these two CFD animations showed in the video were calculated using M-STAR CFD in less than 3 hours each.
In summary, unsteady CFD simulations using LES turbulence model offers an unparalleled pathway to tackle free surface problems, leading to more accurate and realistic results. It represents a significant stride towards the ultimate goal of simulations: not just to mimic the real-world phenomena, but to comprehend, predict, and control them more effectively.