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Spectrum concepts are employed to study the selective effect of a stream contraction on longitudinal and lateral turbulent velocity fluctuations. By consideration of the effect of stream contraction on a single plane wave, the effect on spectrum and correlation tensors of the turbulence is determined. Weak turbulence and an inviscid fluid are postulated; compressibility of mean flow only is taken into account. For axisymmetric contraction and isotropic initial turbulence, explicit results are obtained. The one dimensional longitudinal spectrum is found to be markedly distorted. The selective effect of contraction on longitudinal and lateral components of turbulence is found to be given uniquely, regardless of details of the isotropic spectrum; comparison with experiment is made.

A theoretical investigation was conducted on jet-induced flow deviation. Analysis is given of flow inclination induced outside cold and hot jets and jet deflection caused by angle of attack. Applications to computation of effects of jet on longitudinal stability and trim are explained. Effect of jet temperature on flow inclination was found small when thrust coefficient is used as criterion for similitude. The average jet-induced downwash over tail plane was obtained geometrically.

Design curves are presented which permit rapid estimation of the lift-curve slope and damping-in-roll derivative for given values of aspect ratio, taper ratio, Mach number, and leading edge sweep.

The analysis of the stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds, given in NACA TN No. l423, is extended to apply to triangular wings having large vertex angles and traveling at supersonic speeds. The lift, rolling moment due to siderlip, and damping in roll and pitch for this more general case have been treated elsewhere on the basis of the theory of small disturbances.

Summary: General formulas are given for propellers for the rate of change of side-force coefficient with angle of yaw and for the rate of change of pitching-moment coefficient with angle of yaw. Charts of the side-force derivative are given for two propellers of different plan form. The charts cover solidities of two to six blades and single and dual rotation. The blade angles range from 15° or 20° to 60°. The equations, and the charts computed from the equations, are based on an unpublished analysis, which incorporates factors not adequately covered in previously published work and gives good agreement with experiment over a wide range of operating conditions. A study of the equations indicates that they are consistent with the following physical interpretation: In developing side force, the propeller acts like a fin of which the area is the projected side area of the propeller, the effective aspect ratio is of the order of 8, and the effective dynamic pressure is roughly that at the propeller disk as augmented by the inflow. The variation of the inflow velocity, for a fixed-pitch propeller, accounts for most of the variation of side force with advance-diameter ratio. The charts may be applied to obtain the rate of change of normal-force coefficient with angle of attack of the axis of rotation if proper account is taken of the upwash or downwash from the wing.

The interaction of a convected field of turbulence with a shock wave has been analyzed to yield the modified turbulence, entropy spotiness, and noise generated downstream of the shock. This analysis generalizes the results of Technical Note 2864, which apply to a single spectrum component, to give the shock-interaction effects of a complete turbulence field. The previous report solved the basic gas-dynamic problem, and the present report has added the necessary spectrum analysis.

Summary: It was realized as early as 1909 that a propeller in yaw develops a side force like that of a fin. In 1917, R.G. Harris expressed this force in terms of the torque coefficient for the unyawed propeller. Of several attempts to express the side force directly in terms of the shape of the blades, however, none has been completely satisfactory. An analysis that incorporates induction effects not adequately covered in previous work and that gives good agreement with experiment over a wide range of operating conditions is presented herein. The present analysis shows that the fin analogy may be extended to the form of the side-force expression and that the effective fin area may be taken as the projected side area of the propeller. The effective aspect ratio is of the order of 8 and the appropriate dynamic pressure is roughly that at the propeller disk as augmented by the inflow. The variation of the inflow velocity, for a fixed-pitch propeller, accounts for most of the variation of side force with advance-diameter ration V/nD.

The damping in roll of cruciform delta wings in supersonic flow has been evaluated by means of small-disturbance (linearized) wing theory; both subsonic and supersonic component stream velocities normal to the leading edges have been considered. In addition, some known two-dimensional results for rotating multibladed laminae have been applied to obtain the loading when the number of panels is changed from four to an arbitrary number, under the restriction of low aspect ratio; the damping in roll has been determined explicitly for three panels. Finally, the damping for an inifinite number of panels has been evaluated without restriction as to aspect ratio or Mach number.