Краткое описание

The self-similar incompressible turbulent boundary-layer flow when the free-stream velocity is specified as a power function of longitudinal coordinate is investigated. In adverse pressure gradient, when the exponent is within a certain limits depending on Reynolds number, the problem has two solutions with different values of the boundary-layer thickness and skin friction, which points to the possibility of hysteresis in near-separating flow. For strong-adverse-pressure-gradient flows, a similarity parameter is established and its threshold value for which the solution moves from one branch to the other is calculated. At strong adverse pressure gradients, the boundary layer acquires a triple-deck asymptotic structure: between the outer and wall regions there arises an intermediate 'gradient' sublayer, in whose outer part the velocity profile obeys the 'square-root' law.