Wave drag of the rear part

The fuselage rear parts have tapering in many cases. The reduced pressure is established on tapered rear parts at supersonic speeds. The factor of wave drag of the fuselage rear part depends on the shapes of outlines, its tapering and aspect ratio, number , and also from aspect ratio of the fuselage cylindrical part . It is more less, than its aspect ratio and number are more.

We shall mark, that wave drag will depend on aspect ratio of a cylindrical part :for fuselage with a short cylindrical part (), because, in this case, flow before the rear part will not have time to become uniform and to accept values of undisturbed flow.

At it is possible to consider, that the rear part is streamlined by undisturbed flow and calculate of the wave drag irrespectively of what body it is located.

Calculation of the wave drag factor for conical rear part is performed by the formula

. (13.12)

For the rear part with any generative lines (close by shape to parabola)

, . (13.13)

In case of the pointed rear part it is necessary to accept in the formulae (13.12) and (13.13).

If the engine is installed in the fuselage rear part, the factors will depend on the shape and parameters of outflowing jet. The jet extending at causes pressure increase near the rear part due to flow deceleration in rear shock waves. It promotes decreasing of .

Дата добавления: 2014-12-16