Ocean Engineering Group/EWRE (8/25/09)

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• Ocean Engineering Group/EWRE (8/25/09)
• Spyros A. Kinnas
• (Google Kinnas Home Page)
• Professor and Director of OTRCs UT Office
• (Offshore Technology Research Center)

Research in the area of computational
hydrodynamics with applications on the prediction
of performance and design of high-speed marine
propulsors, modeling of cavitation, and wave/body
interaction.

• Teaching
• CE358 Introductory Ocean Engineering (Fall 09)
• CE319F Elementary Fluid Mechanics
• CE397 Theory of Propulsors (NEW wind/tidal
  turbines -Spring10)
• CE380T Computational Environmental Fluid
  Mechanics (tent. Spring 11)
• CE380P Boundary Element Methods (tent. Spring
  12)

• Facilities
• Computational Hydrodynamics Laboratory (ECJ
  8.502) with 2 computer clusters an older one of
  16-node 2-CPU each, and a new 16-node 2-Quad-core
  CPU each

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Some recent marine propulsors
Contra-rotating props
Podded prop
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and some water-turbines (used to generate
energy from ocean currents)
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Water-jet Propulsors
Direction of boat
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Axial Flow Water-jet Propulsor
Inflow
Stator
Rotor
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Surface-piercing (or cleaver) propellers
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For high-speed propellers cavitation is often
inevitable
Tip vortex
Sheet

• Cavitation can accelerate erosion of blades,
  produce noise, or result in sudden loss of thrust
• However, allowing for some cavitation can
  increase efficiency

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Two methods to model flow
Boundary Element Method (addressed in CE380P)
Finite Volume Method (addressed in CE380T)

• BEM can only deal with inviscid flow. The effects
  of viscosity are evaluated via coupling with
  integral boundary layer methods
• FVM needs a very large number of cells to
  resolve boundary layer within acceptable accuracy

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BEM vs. FVM(application to surface-piercing
hydrofoil)Vinayan, PhD09, UT/OEG

• BEM takes 16 mins on a single processor
• FVM (Fluent) takes 36 hours running parallel in 6
  processors

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Validation with Experiments Surface-Piercing
Propeller M841B
Comparison of ventilation patterns
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Model of water-jet pump performance(Sun, PhD
08, UT/OEG)
Torque on rotor vs. flow-rate
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Prediction of performance of tidal turbines

• Comparisons of the predicted thrust coefficient
  and power coefficient for varying TSRwR/V

Cthrust vs. TSR
Cpower .vs. TSR
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Prediction of Cavitation
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Floating Production systems for Storage and
Offloading (FPSO)

FPSO Hulls can suffer from excessive Roll
Motions (periodic angular motions about the
longitudinal axis)
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Bilge keels are used to mitigate roll
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Model of viscous flow around bilge keels and
their effect on damping (Yu, PhD 08, UT/OEG)
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Model of viscous flow around bilge keels and
their effect on damping (NS-2D/-3D UT/OEGs
method)(Yu, PhD 08, UT/OEG)
Damping coefficient vs. roll frequency
BEM is VERY INACCURATE in the case of roll
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• Fall 09 Opportunities in OEG

• 3 full-time GRAs (2 committed/ 1 available)
• Computational methods (BEM/FVM) for the
  prediction of performance of marine propulsors
  (separated flows, leading edge vortex, cavitating
  flows, tip gap leakage flows, and 3-D boundary
  layer analysis on blades). Requires strong
  background in fluid mechanics, calculus, computer
  programming.