Vortex Effects in the Dynamics of Underwater Weapons

Abstract

As the control and mobility of submarines are improved to meet the challenges of the 21st-century security environment, so the capabilities of underwater weapons must keep pace with these developments. An underwater weapon is typically propelled by a pump-jet, controlled by an arrangement of movable lifting surfaces, and stabilized by fixed fins. The propulsor, fins, and control surfaces are situated close together at the tail, and close to the axis of the weapon due to the requirements for weapons to be launched through tubes. The control and propulsion components form a closely coupled hydrodynamic system in which the rate of fluid flow through the propulsor strongly affects both the propulsion and the control characteristics of the weapon. Vortices are generated by the cylindrical body and fins of the weapon during maneuvers. These are intimately linked with the rest of the flow field generated by the vehicle. This study seeks to assess the degree to which the maneuvering forces experienced by the vehicle are affected by the vortices, and how these are modified by the effect of the propulsor and control systems. A detailed model of the propulsor has been developed using stage interfaces to construct a fluid dynamic model of the duct, working rotor, and stator, with resolved flows around the blades. This is a significant improvement over models that used a momentum source for the effect of the rotor and stator, but did not include the blade flows. This study shows that the CFD method can predict propulsion characteristics. The modeling of the complete, three-dimensional vehicle with working propulsor, at angles of yaw, enables the matching of CFD models for the vehicle and propulsor, the computation of forces at yaw angles, and validation of the vehicle flow through comparison with measured data. (10 figures, 3 refs.)

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 2003
Accession Number
ADA419104

Entities

People

  • A. P. Steer
  • P. A. Lyes

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Boundaries
  • Boundary Layer
  • Computational Fluid Dynamics
  • Control Surfaces
  • Control Systems
  • Dynamics
  • Flow
  • Flow Fields
  • Fluid Dynamics
  • Fluid Flow
  • Geometry
  • Layers
  • Measurement
  • Pressure Distribution
  • Symmetry
  • Three Dimensional
  • Vehicles

Readers

  • Aerodynamics.
  • Control Systems Engineering.
  • Marine Hydrodynamics