Instabilities associated with fluid handling and operation in liquid rocket propulsion systems and test facilities usually manifest themselves as structural vibrations and may cause structural damage such as the cracks observed in the space shuttle hydrogen feed liners. While the source of the instability is directly related to the performance of a component such as a turbopump, valve or a flow control element, the associated pressure fluctuations as they propagate through the system have the potential to amplify and resonate with natural modes of the structural elements and components of the system. The innovation described in this proposal directly relates to an innovative multi-level approach that involves integration of analysis, at both the component and systems level, into a unified simulation framework. The primary source of the unsteadiness is modeled with a high-fidelity hybrid RANS/LES based CFD methodology that has been previously used to study instabilities in feed systems. System response to the driving instability will be simulated through a lumped element modeling (LEM) technique that will approximate the behavior of all the distributed elements that constitute the system.