HOS-NWT enables the possibility to use an arbitrary wavemaker mtion described with specific files. This is available from the input file of HOS-NWT input_HOS-NWT.dat with the parameter icase (file_name is the wavemaker file name)

• icase=3 - file_name.dat describes the frequency components of linear waves generated by wavemaker and file_name.cfg describes the configuration of wavemaker
• icase=31 - file_name.txt is an output of control software used in ECN Wave Basin
• icase=32 - file_name.txt is an output of control software used in ECN Towing Tank
• icase=33 - file_name.txt is an output of control software used in other tanks

This is the basic description of wavemaker motion using file. The HOS-NWT's user have to give two files described hereafter

• file_name.cfg: describes the wavemaker configuration. One value per line (real value unless specified):

  • rnum is an integer
  • clock defines the clockrate (Hz) of the wavemaker motion
    • Previous parameters define frequency spacing df = clock/2^rnum
  • depth is the depth of the wave tank
  • ramp defines length of time ramp in number of cycles (i.e. ramp = Tramp*clock) (useless for now, uses input_HOS-NWT.dat information)
  • typ_ramp [characters], defines type of ramp, use lin (useless for now uses input_HOS-NWT.dat information)
  • cutoff_low defines the low frequency cut-off
  • cutoff_high defines the high frequency cut-off
  • Ly gives the beam of the wave tank (in m)
  • typ_wmk [characters], choose between: hinged and piston
  • hinge defines for hinged wavemaker the rotation axis distance (>= 0)

• file_name.dat gives the frequency description of linear waves generated by wavemaker motion (i.e. in frequency domain this is the wavemaker motion multiplied by transfer function of the chosen wavemaker ; note that no additional phase shift is applied (this is the wave at x=0)). Each line corresponds to a frequency and should contain (separated with commas)

  • n_harmo [integer]: number of present harmonic (i.e. f=n_harmo*df)
  • f: frequency (f=n_harmo*df)
  • ampli: amplitude of the component
  • angle: angle of the component (deg)
  • phase: phase of the component (rad) [-π ; π]

This configuration is specific to the wave tanks of Ecole Centrale Nantes (ocean wave basin or towing tank) or tanks using same control software of wavemaker motion. The wavemaker motion control software developed by Edinburgh Designs Limited allows a specific output under .txtfile format which may be given as input to HOS-NWT. This way, the reproduction of an experiment conducted is those tanks is straightforward, using the exact same wavemaker motion in physical wave basin and the Numerical Wave Tank.