Flow Structure Near the Bow of a Two-Dimensional Body

Flow near a blunt ship's bow is experimentally investigated by studying the flow in front of horizontal surface-piercing cylinders. A bore-like structure develops at the bow of a cylinder when it is immersed in a uniform stream. Observations indicate that the leading edge of this bow wave coincides with a point at which the main flow separates from the free surface. Experimental measurements of the location of the wavefront and the slope of the free surface at the wavefront are in fair agreement with existing theoretical predictions. Power spectra of the time records of the bow-wave elevation show a characteristic oscillation frequency at Froude numbers above a critical value. The bow-wave oscillation is a function of the cross-sectional shape of the two-dimensional body, the draft, and, to a lesser extent the flow velocity. The inception of the oscillation depends on the Reynolds number, but the characteristic frequency is governed by inertial and gravitational forces.