Computational Towing Tank Procedures for Single Run Curves of Resistance and Propulsion

A procedure is proposed to perform ship hydrodynamics computations for a wide range of velocities in a single run, herein called the computational towing tank. The method is based on solving the fluid flow equations using an inertial earth-fixed reference frame, and ramping up the ship speed slowly such that the time derivatives become negligible and the local solution corresponds to a quasi steady-state. The procedure is used for the computation of resistance and propulsion curves, in both cases allowing for dynamic calculation of the sinkage and trim. Computational tests are performed for the Athena R/V model DTMB 5365, in both bare hull with skeg and fully appended configurations, including two speed ramps and extensive comparison with experimental data. Comparison is also performed against steady-state points, demonstrating that the quasisteady solutions obtained match well the single-velocity computations. A verification study using seven systematically refined grids was performed for one Froude number, and grid convergence for resistance coefficient, sinkage, and trim were analyzed. The verification study concluded that finer grids are needed to reach the asymptotic range, though validation was achieved for resistance coefficient and sinkage but not for trim. Overall results prove that for medium and high Froude numbers the computational towing tank is an efficient and accurate tool to predict curves of resistance and propulsion for ship flows using a single run. The procedure is not possible or highly difficult using a physical towing tank suggesting a potential of using the computational towing tank to aid the design process.

[1]  D. T. Greenwood.  Principles of dynamics , 1965 .

[2]  L. B. Crook,et al.  Powering Predictions for the R/V ATHENA (PG 94) Represented by Model 4950-1 with Design Propellers 4710 and 4711 , 1981 .

[3]  Douglas S. Jenkins,et al.  Resistance Characteristics of the High Speed Transcom Stern Ship R/V athena in the Bare Hull Condition, Represented by DTNSRDC Model 5365 , 1984 .

[4]  A. Gosman,et al.  Solution of the implicitly discretised reacting flow equations by operator-splitting , 1986 .

[5]  V. C. Patel,et al.  A viscous-flow approach to the computation of propeller-hull interaction , 1988 .

[6]  Z. Warsi.  Fluid dynamics: theoretical and computational approaches , 1993 .

[7]  F. Menter.  Two-equation eddy-viscosity turbulence models for engineering applications , 1994 .

[8]  Jun Shao,et al.  Quantitative V&V of CFD simulations and certification of CFD codes , 2006 .

[9]  Ralph Noack,et al.  SUGGAR: A General Capability for Moving Body Overset Grid Assembly , 2005 .

[10]  Akihiro Kanai,et al.  Finite-difference simulation of green water impact on fixed and moving bodies , 2005 .

[11]  Frederick Stern,et al.  Flow pattern around an appended tanker hull form in simple maneuvering conditions , 2005 .

[12]  E. Campana,et al.  Shape optimization in ship hydrodynamics using computational fluid dynamics , 2006 .

[13]  David A. Boger,et al.  Prediction of Hydrodynamic Forces and Moments for Underwater Vehicles Using Overset Grids , 2006 .

[14]  Frederick Stern,et al.  RANS simulation of a container ship using a single-phase level-set method with overset grids and the prognosis for extension to a self-propulsion simulator , 2006 .

[15]  Frederick Stern,et al.  Unsteady RANS simulation of the ship forward speed diffraction problem , 2006 .

[16]  Pablo M. Carrica,et al.  URANS simulations for a high-speed transom stern ship with breaking waves , 2006 .

[17]  F. Stern,et al.  Ship motions using single-phase level set with dynamic overset grids , 2007 .

[18]  F. Stern,et al.  Phase-Averaged PIV for the Nominal Wake of a Surface Ship in Regular Head Waves , 2007 .

[19]  IIHR-Hydroscience.  Quantitative V & V of CFD Solutions and Certification of CFD Codes , 2007 .

[20]  Frederick Stern,et al.  An unsteady single‐phase level set method for viscous free surface flows , 2007 .