Angle of divergence

The spread of a jet is the angle of divergence of the airstream after it leaves the outlet. The outlet design may be for horizontal or vertical spread or both. 

Angle of divergence The leaving angle of an air jet from an outlet, or the angle of change in a ductwork section. 

Jet spread The angle of divergence of a jet from its point of origin. 

Angles of divergence or convergence in enlargements or contractions in pipe systems, degrees... 

Consider the simplest kind of collimator (Fig. 5-8), consisting of two circular apertures of diameter ci separated by a distance w, where w is large compared to d. If there is a point source of radiation at S, then all the rays in the beam from the collimator are nonparallel, and the beam is conical in shape with a maximum angle of divergence given by the equation... 

Pressure recovery. If the flow through the venturi meter were frictionless, the pressure of the fluid leaving the meter would be exactly equal to that of the fluid entering the meter and the presence of the meter in the line would not cause a permanent loss in pressure. The pressure drop in the upstream cone — pj would be completely recovered in the downstream cone. Friction cannot be completely eliminated, of course, and a permanent loss in pressure and a corresponding loss in power do occur. Because of the small angle of divergence in the recovery cone, the permanent pressure loss from a venturi meter is relatively small. In a properly designed meter, the permanent loss is about 10 percent of the venturi differential Pa Pb and approximately 90 percent of the differential is recovered. 

Figure 3.1. The schemes of cylindrical (a) and divergent-convergent (b) apparatus, y - the angle of divergent opening Ra = da/2 - radius of wide part (of divergent) Rt = d /2 - radius of narrow part (convergent) 1-8 - apparatus parts I-IV - divergent-convergent sections.

For simplicity, let us restrict ourselves to the case where the divergence of the incident beam is low and the term tj can be neglected. The intensity of the reflected beam will then be proportional to the width of the illuminated surface of the monochromator (or to the angle of divergence of the incident beam A g). With this condition, Eq. (1) becomes... 

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