Ship’s Wake on a Finite Water Depth in the Presence of a Shear Flow

The ship’s wake in the presence of a shear flow constant vorticity at finite water depth is investigated by expanding Whitham-Lighthill kinematic theory. It has been established that structure wave ship radically depends on Froude number Fr (in terms depth) and especially critical Frcr, which magnitude direction flow. At its subcritical values Fr<Frcr two types waves are presented: long transverse short divergent inside wedge area with an angle depending For supercritical range Fr>Frcr only presented region. Critical Frcr variable mostly collinear path component flow: it decreases unidirectional increases counter current. expands increase narrows oncoming mode motion Fr<Frcr. Wake decreased for crests almost finally narrow wake. value Fr=Frcr, total 1800 directed parallel to motion. crossing gives strong asymmetry An perpendicular leads difference between angles arms.