Divergent ship bow waves were simulated experimentally with a two-dimensional wavemaker that employs a flexible wave board. The wavemaker was programmed so that the wave board created a time sequence of shapes that simulated the line of intersection between one side of the hull of a slender ship model moving at constant speed and an imaginary vertical plane oriented normal to the ship model track. The time history of the water surface shape was measured with a cinematic laser-induced fluorescence technique for eight Froude numbers (FD = U/, where U is the forward speed of the equivalent three-dimensional ship model, g the acceleration of gravity and D the ship model draft). The waves produced ranged from small-amplitude non-breaking waves at the lowest Froude numbers to plunging breakers at the highest Froude numbers. These waves are strongly forced and at the higher Froude numbers begin breaking before leaving the wave board. The time histories of various geometric characteristics of the water surface shape including the hull contact line, the wave crest, the plunging jet and the splash zone, which is here defined as both the turbulent zone on the front face of the wave in the spilling breakers and the turbulent zone generated ahead of the jet impact point in the plunging breakers, were measured. The phase speed of the primary wave generated during each run ranged from 2.56Uwl (where Uwl is the maximum speed of the wave board at the undisturbed water level in the tank) at the lowest Froude number to about 1.7Uwl at the three highest Froude numbers. The maximum heights of the primary wave, the contact point on the wavemaker and the splash zone increased in a nearly linear fashion with increasing FD. In the cases with plunging jets, the jet tip trajectory was parabolic with a vertical acceleration ranging from 0.6g at FD = 1.467 to 0.8g at FD = 1.817 (the highest Froude number).
Ship bow waves simulated experimentally with a 2D+T wave maker were investigated experimentally. Wave profile measurements are presented for a range of equivalent full-scale ship speeds ranging from 16.5 to 27 knots. At the beginning of the wave maker motion, the water surface rises rapidly up the surface of the wave board which represents the hull of the equivalent ship model. The maximum rise height and the rate of rise increase with increasing equivalent ship speed. Later in the wave maker motion, this point of maximum water height moves away from the wave board and forms the primary crest in the wave pattern. This crest moves at a speed that is about 1.8 times the maximum speed of the wave board. At the higher speeds, this wave crest evolves into a strong plunging breaker with a jet that hits the water surface ahead of the breaker, creating a large splash and entraining large amounts of air. The temporal histories of various geometrical characteristics of the breaker are presented.
In the published article Shakeri et al. (2009) the title should read as above (i.e. ‘wave maker technique’, not ‘wave marker technique’ as in the published article).
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