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The numerical solution of the problem of flow past a plate whose surface travels in the opposite direction to the stream is obtained under the assumption that the surface velocity is higher than the free-stream velocity. The limiting flow diagram as t → ∞ is predicted and justified.

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Experimental studies indicate that separation formations exist in a diversity of forms [1]. Even in the case of a flow past bodies of uncomplicated configuration the structure of the separation formation has not yet been studied sufficiently and so a priori systems of separating flow must be used in numerical calculations. The experimental study of this problem, therefore, is applied as well as cognitive importance.In a water tunnel with a throat measuring 150 • 150 mm we studied the flow past a model consisting of two plates, connected so that the plane passing through the trailing edge of the fhst plate and the leading edge of the second was perpendicular to plane of the fast (Fig. 1). The plates were separated by a gap. The fast plate, set up along the flow, was flat and the second was curved along a circular arc. The leading edge of the second plate was profiled to eliminate breakaways. Drainage tubes with a dye to visualize the flow were connected to the trailing edge of the fh-st plate and the leading edge of the second. The second plate was 85 mm long and its radius of curvature was 55 mm.Our aim here is to study the interaction of the boundary layers formed on the two plates. A typical pattern of this interaction is shown in Fig. 2. This interaction evidently should model the flow in the vicinity of the gap between a wing and a flap. The flow past such a configuration in a particular range of Reynolds numbers Re leads to an isolated separation [2].The flow has two characteristic scales: l is the length of the first plate, which was 100 mm in the given case, and h ,~ 1 is the distance between the plates. The entire region of flow can thus be divided into two subregions: an external subregion associated with the total flow past the model and an internal subregion associated with the flow around the gap.The flow in the external region has a characteristic Reynolds number of the order of 103. A Blasius boundary layer forms on the front plate and its thickness 5 varies with the distance from the leading edge x by the law [3]