Computation of the 3-D Unsteady Flow Past Deforming Geometries

Abstract

A 3-D incompressible unsteady flow solver based on simple finite elements with adaptive remeshing and grid movement for both moving and deforming surfaces is described. We demonstrate the combination of adaptive remeshing technique with the incompressible flow solver by computing the flow past an undulating eel in 2-D and past a swimming bluefin tuna in 3-D. It is clear that proper choice of the amplitude and frequency of undulation is necessary for positive thrust production in the eel. Unsteady flow of the swimming tuna with caudal fin oscillation and quasi-steady state flow at several caudal fin positions are computed. Comparison of these results show that the unsteady flow is considerably different in both magnitude and trend suggesting that unsteady flow about moving deforming bodies is not amenable to spatial decomposition or temporal, quasi-steady approximations.

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Document Details

Document Type
Technical Report
Publication Date
Oct 20, 1997
Accession Number
ADA331865

Entities

People

  • Rainald Löhner
  • Ravi Ramamurti
  • William C. Sandberg

Organizations

  • United States Naval Research Laboratory

Tags

DTIC Thesaurus Topics

  • Amplitude
  • Computations
  • Fish
  • Fluid Dynamics
  • Frequency
  • Geometry
  • Incompressible Flow
  • Oscillation
  • Pressure Distribution
  • Simulations
  • Steady Flow
  • Steady State
  • Swimming
  • Three Dimensional
  • Two Dimensional
  • Undulation
  • Unsteady Flow

Fields of Study

  • Physics

Readers

  • Aquatic Ecology
  • Computational Fluid Dynamics (CFD)
  • Fluid Mechanics and Fluid Dynamics.