Tactical Alteration of Blade Tonals in Underwater Vehicles Using Active Control of Biomimetic Muscles
Abstract
The goal of this project is to achieve stealth by altering blade tonals, which occur due to the operation of a propulsor in a nonuniform flow, using active control of biomimetic muscles. Stealth is accomplished by many biological organisms through the introduction of suitable unsteady hydrodynamics. By modulating additional surfaces, these organisms appear to affect lift, drag, and related wake producing features, a combination of which may lead to a modification of the underlying acoustic characteristics. The question is whether the distillation of these features and their incorporation in an underwater propulsor for the purpose of noise reduction is a feasible endeavor. In this project, to achieve stealth, active control will be used, which consists of intentional articulation of suitable surfaces or boundary conditions in the vehicle using external energy. One of the main sources of noise production is direct radiation. Radiated noise is due to several sources, which include (i) fluctuating volumes, (ii) fluctuating forces, and (iii) turbulence. Fluctuating thrust and side forces are produced due to the operation of a propulsor in a non-uniform wake. In particular, a wake deficit is produced due to the presence of a stator or a guide-vane in a uniform flow 1,2. When this wake deficit is incident on the rotor blade, it generates an unsteady force, resulting in noise. Each rotor blade-geometry results in a specific spectrum of noise, and therefore generates a specific ""signature" of the radiated noise.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2005
- Accession Number
- ADA438877
Entities
People
- Anuradha M. Annaswamy
Organizations
- Massachusetts Institute of Technology