2   5  7   11          21
    - --- -- ---- ---------- --------
   |X|   |  |WRMP|XXXXXXXXXX|        |
    - --- -- ---- ---------- --------
       |  |   |                 |
       |  |   |                 |
       |  |   |                 |_(1) Time (tw) before which the wave ramp is effective (F10.0)
       |  |   |
       |  |   |_Compulsory Data Record Keyword (A4)
       |  |
       |  |_Optional User Identifier (A2)
       |
       |_Compulsory END on Last Data Record in Data Category (A3)

(1) The wave ramp is introduced to reduce the transient motion of the structure at the beginning of a time domain analysis. When this data record is defined, the wave ramp takes effect from t = 0.0 to t = t_w, during which a wave ramp factor f (0.0 < f < 1.0) is calculated and multiplied to the wave frequency forces.

The wave ramp factor f is calculated by

At t = 0, the wave ramp factor is 0.0 and at t = t_w, the factor is 1.0. If t_w is omitted in the WRMP data record, the program will default to t_w = wave period for regular waves; for irregular waves in Naut, the default value for t_w will be the highest period of all the wave components in the spectrum.