Analysis of Wave induced Forcing on a Submerged Body at Various Pitch Angles

Abstract

This experiment aimed to quantify the effect of pitch angle on the linear and nonlinear wave-loading of a submerged, cylindrical body. The lower-frequency nonlinear loads that occur in a multi-component seaway were also investigated in greater detail for the zero-pitch case. Unmanned Underwater Vehicles (UUVs) are of increasing interest for use in littoral zones so performance parameters need to be well defined for better design and control. A model was subjected to single and two-component wave trains for pitch angles between -15 and +15 at a depth of 1.5D (model diameter). The results show a negligible difference in vertical force and pitch moment for this range of pitch angles. There was a small increase in drag force at 15. The two wave tests validated the use of superposition for predicting linear loads in a multi-component seaway. The smaller low-frequency, nonlinear drag and vertical forces have similar trends with a maximum around a 0.4 Hz frequency difference. The nonlinear pitch moment increases with frequency difference over the range tested. The low-frequency nonlinear loads show a dependence on frequency difference.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2020
Accession Number
AD1114509

Entities

People

  • Bennitt L. Hermsen

Organizations

  • Naval Postgraduate School

Tags

Communities of Interest

  • Air Platforms
  • Autonomy
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Accuracy
  • Axial Loads
  • Control Systems
  • Coordinate Systems
  • Diameters
  • Engineering
  • Environment
  • Frequency
  • Geometry
  • Load Cells
  • Resonant Frequency
  • Two Dimensional
  • Underwater Vehicles
  • Unmanned Maritime Systems
  • Unmanned Systems
  • Unmanned Underwater Vehicles
  • Vehicles

Fields of Study

  • Engineering

Readers

  • Acoustical Oceanography.
  • Control Systems Engineering.
  • Marine Hydrodynamics

Technology Areas

  • Autonomy