Experiment

Towing-tank experiments of coupled pitch and heave motions are presented for a surface combatant advancing in regular headwaves.  The data includes ballasting parameters, encounter frequency, time histories, Fourier series amplitudes, and pitch and heave transfer functions and phase.  The geometry of interest is DTMB model 5512, which is a 1/46.6 scale geosim of DTMB model 5415 (DDG-51) with L_pp = 3.048 m.  The experiments are performed in a 3 x 3 x 100 m towing tank equipped with a plunger-type wavemaker.  The test program is undertaken to create a validation dataset for unsteady Reynolds-averaged Navier Stokes simulations including rigorous and comprehensive uncertainty assessment of the experimental results following standard procedures.  Results indicate that the regular headwaves are in the linear regime except for a few high-steepness cases.  Pitch and heave responses are mostly independent of wave steepness, however, some nonlinear responses are identified mainly for high-speed, short-wavelength test cases.

Data, equipment, and conditions

Sample image

Overhead view of model 5512, Krypton target, and pitch and heave mount

Download 5512 geometry

Click on the image below to download an .iges file of the appended model 5415/5512

Sample data

Pitch (top) and heave (bottom) transfer functions and phase and uncertainty error bars for Fr = 0.28 and a range of encounter frequencies and wave steepnesses

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References

Irvine, M., Longo, J., and Stern, F., (2006), "Pitch and Heave Tests and Uncertainty Assessment for a Surface Combatant in Regular Head Waves," Journal of Ship Research, submitted.  (pdf)

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