Description of velocity fields in front of exhaust axisymmetric inlets by means of new empirical equations

New empirical equations for the prediction of air velocity in a symmetry plane of freely suspended circular exhaust openings (both plain and flanged) are presented. The new equations here introduced are derived from experimental studies carried out by the authors. In consideration of the difficulty in describing simply and accurately the velocity field by means of a single equation, velocity gradients are provided along lines parallel to the opening axis (i.e. perpendicular to the plane containing the circular suction aperture). These velocity decays allow the user/designer to predict with satisfactory accuracy the air velocity also outside the hood axis, by means of easy-to-use equations.