Airplane wings oscillate when impacted by wind gusts or turbulence. Most airplanes store fuel in their wings, and this oscillation causes the fuel to slosh around in the tanks. It is possible to use this sloshing to provide a damping force to the wings, which would enable future wing designs to be lighter and cheaper.
Michel et al. developed a computational model of violent fluid sloshing and simulated two different liquids in three dimensions to compare the effects of viscosity.
“In violent sloshing flows, the liquid interface experiences large deformations and continuous breaking phenomena during several oscillation cycles,” said author Danilo Durante. “At the same time, the Reynolds number involved is high enough to induce the development of numerous and energetic turbulent structures.”
To simulate this complex environment, the authors adapted a Smoothed Particle Hydrodynamics model by incorporating an embedded turbulent model. The combined result was able to accurately simulate a sloshing fluid tank, agreeing with simplified experimental studies with limited degrees of freedom.
The model identified several unique behaviors of the sloshing flow, including a large number of vortices generated by water sloshing that weren’t present in the higher viscosity oil simulation, which explains water’s surprisingly high energy dissipation rate.
After further validation of the model, the authors are planning to use it to study the wing and fuel tank environment, simulating the interactions between the sloshing fuel and the solid, flexible wing structure. They plan to compare these results to more advanced experimental models.
Source: “Energy dissipation in violent three dimensional sloshing flows induced by high-frequency vertical accelerations,” by Julien Michel, Danilo Durante, Andrea Colagrossi, and Salvatore Marrone, Physics of Fluids (2022). The article can be accessed at https://doi.org/10.1063/5.0114635.