Author(s)

T. FOUREST, M. ARRIGONI, E. DELETOMBE, J. DUPAS & J-M. LAURENS

Abstract

To reduce the vulnerability of both civilian and military aircraft, it is important to take the hydrodynamic ram (HRAM) effect into account when designing their fuel tanks. HRAM is especially dangerous for liquid- filled thin walled lightweight structures that cannot be armoured due to weight penalty reasons. However, the response of the tank structure during HRAM events depends on a coupling model between fluid and structure. Water is generally used as a liquid candidate for experimental observations of HRAM, since it is a safe and affordable solution. However, its characteristics in thermal transfers are far different from the ones of hydrocarbons, and it may influence the bubble behaviour and thus its resulting loading on the tank walls. A good understanding of all these aspects is still needed to enhance the tank designs. Similarities in bubble behaviour between HRAM and underwater explosion situations were observed in recent high-speed tank penetration/water entry experiments. A confined version of the Rayleigh-Plesset equation – which is classically used for bubble dynamics analysis (including underwater explosion) – has been previously proposed to simulate a bubble created by an HRAM event. The work the presented work is a first attempt to the estimation of the influence of thermal effects in HRAM processes, by using the Rayleigh-Plesset equation in confined regime.

Keywords

ballistic impact, cavitation, fuel-filled tank, hydrodynamic ram, Rayleight-Plesset equation, thermal effects