Suppressing the Pressure-Source Instability in Modeling Deep-Draft Vessels with Low Under-Keel Clearance in FUNWAVE-TVD

Abstract

This Coastal and Hydraulics Engineering Technical Note (CHETN) documents the development through verification and validation of three instability-suppressing mechanisms in FUNWAVE-TVD, a Boussinesq-type numerical wave model, when modeling deep-draft vessels with a low under-keel clearance (UKC). Many large commercial ports and channels (e.g., Houston Ship Channel, Galveston, US Army Corps of Engineers [USACE]) are traveled and affected by tens of thousands of commercial vessel passages per year. In a series of recent projects undertaken for the Galveston District (USACE), it was discovered that when deep-draft vessels are modeled using pressure-source mechanisms, they can suffer from model instabilities when low UKC is employed (e.g., vessel draft of 12 m(1) in a channel of 15 m or less of depth), rendering a simulation unstable and obsolete. As an increasingly large number of deep-draft vessels are put into service, this problem is becoming more severe. This presents an operational challenge when modeling large container-type vessels in busy shipping channels, as these often will come as close as 1 m to the bottom of the channel, or even touch the bottom. This behavior would subsequently exhibit a numerical discontinuity in a given model and could severely limit the sample size of modeled vessels. This CHETN outlines a robust approach to suppressing such instability without compromising the integrity of the far-field vessel wave/wake solution. The three methods developed in this study aim to suppress high-frequency spikes generated nearfield of a vessel. They are a shock-capturing method, a friction method, and a viscosity method, respectively. The tests show that the combined shock-capturing and friction method is the most effective method to suppress the local high-frequency noises, while not affecting the far-field solution.

Open PDF

Document Details

Document Type
Technical Report
Publication Date
May 01, 2021
Accession Number
AD1133356

Entities

People

  • Fengyan Shi
  • Matt Malej

Organizations

  • Engineer Research and Development Center

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Army
  • Army Corps Of Engineers
  • Cargo Ships
  • Coastal Engineering
  • Coefficients
  • Elevation
  • Engineering
  • Engineers
  • Equations
  • Far Field
  • Frequency
  • Friction
  • Geometry
  • Instability
  • Near Field
  • Pressure Gradients
  • Shallow Water
  • Shape
  • Ships
  • Therapy
  • Two Dimensional
  • Viscosity
  • Water

Readers

  • Computational Fluid Dynamics (CFD)
  • Fluid Mechanics and Fluid Dynamics.
  • Maritime Security/Maritime Homeland Security