<p>The arrangement (1) has a flow acceleration device with a flow guiding device (9) that extends within an outer diffuser (2). The flow acceleration device forms a manifold (11) with its outer surface (10) facing an inner surface (8) of the outer diffuser, and a section of the inner surface of the outer diffuser, where a portion of a boundary layer flow formed on the inner surface of the outer diffuser is acceleratable in a main flow direction in such a manner that a flow separation is stopped on the inner surface of the outer diffuser.</p>
