# On the Efficacy of Turbulence Modelling for Sloshing
###### Abstract  
As part of a wider project to understand the applicability of utilising slosh-based damping for wing-like structures, simulations of partially filled tanks subjected to harmonically oscillating and vertical motion are presented. The Volume of Fluid modelling approach is used to capture the air-water interface and different turbulence models based on the Reynolds Averaged Navier-Stokes equations employed. No-model simulations are also conducted to demonstrate the efficacy of using turbulence models in the simulation of sloshing flows. Accuracy of the models is assessed by comparing with recent well-validated experimental data in terms of the damping effect of the sloshing. A wide range of excitation amplitudes are considered in the study to demonstrate the effectiveness of different turbulence models in representing the flow feature of weak and very violent sloshing. The results show that standard turbulence models can produce an excessive dissipation, especially at the interface, leading to inaccuracies in the estimation of sloshing dynamics of the violent sloshing. This issue is absent in the no-model simulations, and better results are obtained for all tested sloshing conditions, suggesting approaches to mitigate this interfacial dissipation within RANS-based modelling is an important consideration for future direction. s +
Footnote †: journal: Applied  
doi:10.3390/app12178851  
Footnote †: journal: Applied  
doi:10.3390/app12178851  
[PERSON] et al. [16], [PERSON] et al. [17] studied the impact load of breaking waves on coastal structures. The survivability of a moored floating production storage and offloading model was assessed by [PERSON] et al. [18]. The coupled rolling motion of a ship with a tank sloshing was studied by [PERSON] et al. [19] and [PERSON] et al. [8], showing a rolling damping effect when the tank's dimension and filling level are carefully chosen. [PERSON] et al. [7] and [PERSON] and [PERSON] [20] investigated the transient damping response of single degree-of-freedom system to different excitation amplitude and filling levels. They showed a high damping response at the start of the transition, which is important to mitigate the aircraft gust loads. Mimicking an aircraft wing, a scaled cantilever beam with partially filled tanks at the tip was developed by [PERSON] et al. [21] to study the damping effect of different filling levels. The experimental measurements can be considered the most reliable approach to study the fluid dynamics of the problem, albeit this is limited by the number and the type of variables that can be realistically quantified. Additionally, for the sloshing problem, scaling from experimental models to full-scale implementation is not trivial [22; 23], and this is especially true in an industrial context. Computational fluid dynamics (CFD) can provide a comprehensive representation of flow features that are usually difficult or impossible to obtain experimentally. Additionally, with appropriate modelling approaches and computational resources, CFD can be used to study full-scale problems. Smoothed Particle Hydrodynamics (SPH) has been used for the modelling of free surface flows, such as sloshing and waves [7; 24; 25; 26; 27; 28]. Level set methods have also been used to define the free surface [29; 30] in sloshing problems. Finite-volume discretisation combined with the Volume of Fluid (VoF) method is available in many commercial and open-source CFD solvers and presents a common methodological approach to solving sloshing-type problems. [PERSON] et al. [31], [PERSON] [32] and [PERSON] et al. [18] used VoF to study waves and their interactions with fixed and floating structures, with a good agreement with experimental data, and the successful use of VoF for sloshing problems was demonstrated in [33; 34; 35; 36; 37; 38; 39; 40]. High-resolution simulations that capture the flow physics down to the Kolmogorov length scale, i.e., direct numerical simulation, can be prohibitively expensive in computational terms.