Theoretical Calculation of the Power Spectra of the Rolling and Yawing Moments on a Wing in Random Turbulence
Abstract
The correlation functions and power spectra of the rolling and yawing moments on an airplane wing due to the three components of continuous random turbulence are calculated. The rolling moments due to the longitudinal (horizontal) ani normal (vertical) components depeni on the span-wise distributions of instantaneous gust intensity, which are taken into account by using the inherent properties of symmetry of isotropic turbulence. The results consist of expressions for correlation functions or spectra of the rolling moment in terms of the point correlation functions of the two components of turbulence. Specific numerical calculations are made for a pair of correlation functions given by simple analytic expressions which fit available experimental data quite well. Calculations are made for four lift distributions. Comparison is made with the results of previous analyses which assumed random turbulence along the flight path and linear variations of gust velocity across the span. The rolling moment due to lateral (side) gusts, which is small, is expressed in terms of the instantaneous value of the gust near the center line of the fuselage, so that the effect of spanwise variation in gust intensity is ignored. The yawing moments are considered to be proportional to the rolling moments with the constants of proportionality given by simple aerodynamic relations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1956
- Accession Number
- ADA380490
Entities
People
- Franklin W. Diederich
- John M. Eggleston
Organizations
- National Aeronautics and Space Administration