CCP-WSI Blind Test Series 5: Numerical Investigation of Isothermal Sloshing in a Circular Tank Using OpenFOAM

Sloshing dynamics in partially filled tanks is a critical concern across various engineering disciplines, including maritime, aerospace, automotive, and industrial applications. This work concerns a series of sloshing test cases using computational fluid dynamics and represents an individual contribution to the CCP-WSI Blind Test Series 5, in which the submitted results are compared against both physical and alternative numerical solutions. Free surface and centre of gravity measurements are presented and the sensitivity to crucial numerical techniques such as turbulence modelling are assessed. Results suggest that capturing the onset of excitation is particularly sensitive to the choice of turbulence model and in some cases the mesh resolution.In offshore shipping, the storage and transport of liquid gas rely on type ‘C’ tanks, which are engineered to withstand extreme cryogenic conditions and high pressures. These specialised tanks play a crucial role in safely handling liquid gas, ensuring its viability as a large-scale energy carrier. Drawing from this expertise, the aviation industry is exploring alternative fuels to mitigate carbon emissions, with liquid hydrogen (LH2) emerging as a promising candidate, which does not emit carbon dioxide under combustion. Additionally, LH2 exhibits a high specific energy density, nearly three times that of conventional aviation fuel, offering an advantage of reduced fuel mass for the same energy content. However, the cryogenic nature of LH2, necessitating storage at temperatures as low as -253°C, presents challenges. One problem is liquid sloshing, which induces complex fluid motions within partially filled fuel tanks, this can lead to significant pressure variations in a cryogenic fuel tank. Understanding and mitigating pressure variations is critical for ensuring stable fuel delivery to aircraft propulsion systems. Sloshing refers to the free-surface motion of a liquid in a container subjected to external excitation (Ibrahim, 2005).This phenomenon is particularly problematic in cryogenic fuel tanks due to thermal and fluid dynamic interactions. As demonstrated in previous experimental studies (Moran et al., 1994; Arndt et al., 2008; Das amp; Hopfinger, (2009), Ludwig et al., 2013), sloshing can disrupt the thermal stratification between liquid and gaseous phases within the ullage space, leading to thermal destratification. This phenomenon is driven by heat and mass transfer between the phases, leading to condensation and subsequently rapid pressure drops. Such pressure drops can induce structural instability and fuel delivery issues, posing risks to aircraft certification and the overall operational efficiency of LH2-fueled aircraft.