The von Karman & Dryden Continuous Gust Spectra Revision A By Tom Irvine Email: tom@vibrationdata.com June 14, 2013 ______________________________________________________________________________ The von Karman gust spectrum (1961) is widely used for design aircraft to withstand continuous random gusts. In particular, FAA Federal Aviation Regulations FAR-25 Appendix G, Continuous Gust Design Criteria, requires a continuous turbulent gust analysis for transport aircraft. The von Karman velocity power spectral density for vertical and lateral gusts is (1a) (1b) / 2 is the cycles/feet f is the frequency (Hz) is the root-mean-square vertical or lateral gust velocity, equal to 85 ft/sec between 0 and 30,000 ft, and then decreasing linearly to 30 ft/sec at 80,000 ft L 2500 ft, an integral length scale of turbulent eddies (FAA, 1988) a 1.330 is the von Karman constant U is the forward aircraft speed The von Karman velocity power spectral density for longitudinal gusts is (2a)
The von Karman & Dryden Continuous Gust Spectra Revision A By Tom Irvine Email: tom@vibrationdata.com June 14, 2013 ______________________________________________________________________________ The von Karman gust spectrum (1961) is widely used for design aircraft to withstand continuous random gusts. In particular, FAA Federal Aviation Regulations FAR-25 Appendix G, Continuous Gust Design Criteria, requires a continuous turbulent gust analysis for transport aircraft. The von Karman velocity power spectral density for vertical and lateral gusts is (1a) (1b) / 2 is the cycles/feet f is the frequency (Hz) is the root-mean-square vertical or lateral gust velocity, equal to 85 ft/sec between 0 and 30,000 ft, and then decreasing linearly to 30 ft/sec at 80,000 ft L 2500 ft, an integral length scale of turbulent eddies (FAA, 1988) a 1.330 is the von Karman constant U is the forward aircraft speed The von Karman velocity power spectral density for longitudinal gusts is (2a)
VK_gust_revA.docx