New Approaches for Reducing Helmholtz Resonance in Submarine Structures

The proposed Phase II effort aims to develop, validate and demonstrate a Computational Fluid Dynamic (CFD) tool capable of predicting the occurrence of Helmholtz resonance in cavities in underwater vehicles. Preliminary validation of the CFD tool and identification of numerical fidelity parameters was carried out in Phase I. Preliminary demonstrations of the feasibility of exerting control by modifying the flow over the cavity was also demonstrated. The Phase II effort will extend the capability of this tool to handle structural deflection effects. This tool will also be used to study, in combination with experiments, a series of control concepts to mitigate the resonance occurring in underwater structures. Towards this end, a program comprising of experiments involving planar field imaging and simulations involving detailed whole field imaging has been proposed. The experiments will be conducted on configurations of interest to the Navy and will involve open cavities as well as those with slotted/slatted openings. Detailed parameterization of the flow and geometry parameters for several control concepts will be obtained from this effort. A study to determine the feasibility of scaling these concepts to full scale is also proposed as an option to determine the direct applicability of this work to “real-life” situations.