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Twenty-First Symposium on Naval Hydrodynamics (1997)
Commission on Physical Sciences, Mathematics, and Applications (CPSMA)

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. "Self-Propelled Maneuvering Underwater Vehicles." Twenty-First Symposium on Naval Hydrodynamics. Washington, DC: The National Academies Press, 1997.

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Twenty-First Symposium on NAVAL HYDRODYNAMICS

Fig. 3 Flow Angle β=tan–1(W/U), Anisotropic Model, Re=4.2×106, α=10°.

Fig. 4 Boundary Layer Normal Stress Profiles, x/L=0.4,Φ=100°, Anisotropic Model, Re=4.2×106, α=10°.

Fig. 5 Boundary Layer Shear Stress Profiles, x/L=0.4,Φ=100°, Anisotropic Model, Re=4.2×106, α=10°.

6.0
RESULTS

Throughout this research effort, computations were carried out in order to validate the code as each additional computational capability and improvement was added. These test cases have ranged from steady state laminar flow over a flat plate to unsteady turbulent flow about a fully appended submarine configuration that included sail, sail plane, four stern appendages, and an actual rotating propeller; and, the coupling of this unsteady flow computation to the 6-DOF computation in order to predict the trajectory of the submarine. The computations performed between these two extremes were cases where analytical solutions or experimental data were available for comparison whenever possible. The solutions were carried out on multiblock grids with structured subgrids, and nearly all of these grids were built using EAGLEView [34]. Moreover, all of the grids were tight with y+ values near surfaces of order one.

6.1
Validation Computations

The ultimate objective of this work, which was the prediction of the trajectory of fully appended self-propelled maneuvering vehicles, involved more complicated flow fields and configurations than those corresponding to the experiments for which measured data were available. Nevertheless, the approach taken, whenever data and time permitted, was to perform rather critical comparisons with the experimental data that were available. For steady state flows, comparisons have been made between numerical results and experimental data that include one or more of the measurements of pressure, skin friction, and/or boundary-layer velocity profiles for geometric configurations that include SUBOFF [35], inflected stern [36], 6:1 prolate spheroid [37], and wing-body junction [38]. These numerical and experimental comparisons are included in [ 4, 18, 19, 20, 39, and 40]. For unsteady flows, comparisons with experimental pressure and velocity measurements have been made with the so-called flapping foil experiment [41]. the 6:1 prolate spheroid in pitch, plunge, and roll maneuvers [42 and 43], an impulsively started cylinder [44], and isolated rotating propellers [45 and 46]. These numerical and experimental comparisons are included in [ 21, 39, 47, 48, and 49]. The quality of agreement for all of the steady and unsteady flow comparisons have been considered reasonable to excellent.

The computations mentioned above that have been carried out for comparisons with experimental data have involved an enormous number of calculations and essentially all of these calculations were performed on workstations that included SGI 75 MHz R8000 processors and IBM RS/6000 Model 560 and 590 processors. Examples of processing speed are given in [20] and include an example of the computation of a

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484
Front Matter (R1-R16)
Opening Remarks (1-4)
Progress Toward Understanding How Waves Break (5-28)
Radiation and Diffraction Waves of a Ship at Forward Speed (29-44)
Nonlinear Ship Motions and Wave-Induced Loads by a Rankine Method (45-63)
Nonlinear Water Wave Computations Using a Multipole Accelerated, Desingularized Method (64-74)
Computations of Wave Loads Using a B-Spline Panel Method (75-92)
Simulation of Strongly Nonlinear Wave Generation and Wave-Body Interactions Using a 3-D Model (93-109)
Analysis of Interactions Between Nonlinear Waves and Bodies by Domain Decomposition (110-119)
Fourier-Kochin Theory of Free-Surface Flows (120-135)
24-inch Water Tunnel Flow Field Measurements During Propeller Crashback (136-146)
Accuracy of Wave Pattern Analysis Methods in Towing Tanks (147-160)
Unsteady Three-Dimensional Cross-Flow Separation Measurements on a Prolate Spheroid Undergoing Time-Dependent Maneuvers (161-176)
Time-Domain Calculations of First-and Second-Order Forces on a Vessel Sailing in Waves (177-188)
Third-Order Volterra Modeling Ship Responses Based on Regular Wave Results (189-204)
Nonlinearly Interacting Responses of the Two Rotational Modes of Motion-Roll and Pitch Motions (205-219)
Nonlinear Shallow-Water Flow on Deck Coupled with Ship Motion (220-234)
Radar Backscatter of a V-like Ship Wake from a Sea Surface Covered by Surfactants (235-248)
Turbulent Free-Surface Flows: A Comparison Between Numerical Simulations and Experimental Measurements (249-265)
Conductivity Measurements in the Wake of Submerged Bodies in Density-Stratified Media (266-277)
Macro Wake Measurements for a Range of Ships (278-290)
Time-Marching CFD Simulation for Moving Boundary Problems (291-311)
Yaw Effects on Model-Scale Ship Flows (312-327)
A Multigrid Velocity-Pressure-Free Surface Elevation Fully Coupled Solver for Calculation of Turbulent Incompressible Flow around a Hull (328-345)
The Shoulder Wave and Separation Generated by a Surface-Piercing Strut (346-358)
Vorticity Fields due to Rolling Bodies in a Free Surface-Experiment and Theory (359-376)
Numerical Calculations of Ship Stern Flows at Full-Scale Reynolds Numbers (377-391)
Near-and Far-Field CFD for a Naval Combatant Including Thermal-Stratification and Two-Fluid Modeling (392-407)
Water Entry of Arbitrary Two-Dimensional Sections with and Without Flow Separation (408-423)
Coupled Hydrodynamic Impact and Elastic Response (424-437)
A Practical Prediction of Wave-Induced Structural Responses in Ships with Large Amplitude Motion (438-452)
Evaluation of Eddy Viscosity and Second-Moment Turbulence Closures for Steady Flows Around Ships (453-469)
On the Modeling of the Flow Past a Free-Surface-Piercing Flat Plate (470-477)
Self-Propelled Maneuvering Underwater Vehicles (478-489)
Spray Formation at the Free Surface of Turbulent Bow Sheets (490-505)
Numerical Simulation of Three-Dimensional Breaking Waves About Ships (506-519)
Generation Mechanisms and Sources of Vorticity Within a Spilling Breaking Wave (520-533)
The Flow Field in Steady Breaking Waves (534-549)
Freak Waves-A Three-Dimensional Wave Simulation (550-560)
Bluff Body Hydrodynamics (561-579)
Large-Eddy Simulation of the Vortical Motion Resulting from Flow over Bluff Bodies (580-591)
The Wake of a Bluff Body Moving Through Waves (592-604)
Low-Dimensional Modeling of Flow-Induced Vibrations via Proper Orthogonal Decomposition (605-621)
Measurements of Hydrodynamic Damping of Bluff Bodies with Application to the Prediction of Viscous Damping of TLP Hulls (622-634)
Hydrodynamics in Advanced Sailing Design (635-660)
Divergent Bow Waves (661-679)
A Method for the Optimization of Ship Hulls from a Resistance Point of View (680-696)
Hydrodynamic Optimization of Fast-Displacement Catamarans (697-714)
On Ships at Supercritical Speeds (715-726)
The Influence of a Bottom Mud Layer on the Steady-State Hydrodynamics of Marine Vehicles (727-742)
A Hybrid Approach to Capture Free-Surface and Viscous Effects for a Ship in a Channel (743-755)
Shock Waves in Cloud Cavitation (756-771)
Asymptotic Solution of the Flow Problem and Estimate of Delay of Cavitation Inception for a Hydrofoil with a Jet Flap (772-782)
Examination of the Flow Near the Leading Edge and Closure of Stable Attached Cavitation (783-793)
Numerical Investigation on the Turbulent and Vortical Flows Beneath the Free Surface Around Struts (794-811)
Steep and Breaking Faraday Waves (812-826)
The Forces Exerted by Internal Waves on a Restrained Body Submerged in a Stratified Fluid (827-838)
Influence of the Cavitation Nuclei on the Cavitation Bucket when Predicting the Full-Scale Behavior of a Marine Propeller (839-850)
Inception, Development, and Noise of a Tip Vortex Cavitation (851-864)
Velocity and Turbulence in the Near-Field Region of Tip Vortices from Elliptical Wings: Its Impact on Cavitation (865-881)
Calculations of Pressure Fluctuations on the Ship Hull Induced by Intermittently Cavitating Propellers (882-897)
Hydroacoustic Considerations in Marine Propulsor Design (898-912)
Prediction of Unsteady Performance of Marine Propellers with Cavitation Using Surface-Panel Method (913-929)
A Comparitive Study of Conventional and Tip-Fin Propeller Performance (930-945)
A New Way of Stimulating Whale Tail Propulsion (946-958)
Effects of Tip-Clearance Flows (959-972)
Experiments in the Swirling Wake of a Self-Propelled Axisymmetric Body (973-985)
Hydrodynamic Forces on a Surface-Piercing Plate in Steady Maneuvering Motion (986-996)
Advances in Panel Methods (997-1006)
Effect of Ship Motion on DD-963 Ship Airwake Simulated by Multizone Navier-Stokes Solution (1007-1017)
Large-Eddy Simulation of Decaying Free-Surface Turbulence with Dynamic Mixed Subgrid-Scale Models (1018-1032)
Fully Nonlinear Hydrodynamic Calculations for Ship Design on Parallel Computing Platforms (1033-1047)
Validation of Incompressible Flow Computation of Forces and Moments on Axisymmetric Bodies Undergoing Constant Radius Turning (1048-1060)
The Validation of CFD Predictions of Nominal Wake for the SUBOFF Fully Appended Geometry (1061-1076)
Appendix-List of Participants (1077-1084)