Hydrofoil Leading Edge Isolation for Vibration and Noise Reduction in Marine Systems

Abstract

A technique for reducing the vibration and noise from hydrofoils subject to unsteady lift is examined experimentally. Since the unsteady lift is known to be concentrated in the leading edge vicinity, a single-stage vibration isolation mount is integrated into a hydrofoil near its leading edge to inhibit the leading edge-generated unsteady forces from being transmitted to the remainder of the foil and any structures coupled to it. A single layer of elastomer forms the mount and is used to isolate the leading 20% chord of the hydrofoil from the remainder of the structure. The hydrofoil is excited into vibration by turbulence from an upstream wake generator in a water tunnel facility. Compared to a nonisolated hydrofoil, vibration reductions up to 10dB in level are recorded on the portion of the hydrofoil isolated from the leading edge.