![]() ![]() ![]() As the first attempt, the work focuses mainly on the identification of the natural frequency and the equivalent slosh mass from the simulations. The purpose of this work is to demonstrate the soundness of a computational-fluid-dynamics approach in modeling the detailed fluid dynamics of tank sloshing and the excellent accuracy in extracting mechanical properties for different tank configurations and at different fill levels. space program, these parameters were computed either from analytical solutions for simple geometries or by experimental testing for the subscale configurations. The typical parameters required by the mechanical model include the natural frequency of the sloshing, sloshing mass, sloshing mass center coordinates, and critical damping coefficient. This mechanical model is then included in the equation of motion of the entire vehicle for guidance, navigation and control analysis. The sloshing dynamics are typically represented by a mechanical model of a spring–mass–damper system. Propellant slosh is a potential source of disturbance critical to the stability of space vehicles. This research constitutes the first fluid-structure modeling of shallow jet spurts which future three-dimensional analyses will expound upon. It is further explained how shallow jet spurts are arrested for impacts at the two extremes of plate rigidity. ![]() Results from the verified model suggest shallow jet spurts have at least a quadratic sensitivity to the fundamental vibrational mode of the impact plate across impact velocities 610 – 1829 m/s (2000 – 6000 ft/s). Development and verification of the 2D axisymmetric model is described relative to trends observed in a prior experimental campaign. ALE3D, a first-principles multi-physics code was employed to model the shallow jet spurt phenomenon with spherical projectiles impacting water-filled tanks faced with aluminum panels, such that the underlying physics and sensitivities could be explored. Such pre-spurts as they have been formerly identified have only been witnessed sporadically in HRAM spurt experiments. Physics based modeling of the hydrodynamic ram (HRAM) fluid deposition process is a key component of such capability, wherein capturing the first instance of fluid spurt, referred to herein as shallow jet spurts, is a core focus. With dry bay fires persisting as a significant contributor to aircraft vulnerability despite chronicled developments in survivability technologies, an accurate fire prediction capability remains paramount for credible vulnerability assessments. ![]()
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