{"id":557327,"date":"2024-11-05T18:17:41","date_gmt":"2024-11-05T18:17:41","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/esdu-040242010\/"},"modified":"2024-11-05T18:17:41","modified_gmt":"2024-11-05T18:17:41","slug":"esdu-040242010","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/esdu\/esdu-040242010\/","title":{"rendered":"ESDU 04024:2010"},"content":{"rendered":"

INTRODUCTION<\/strong><\/p>\n

This Item presents an introduction to rigid aeroplane response
\nto gusts and atmospheric turbulence, together with the design
\ncriteria required to satisfy airworthiness requirements for both
\ntypes of disturbance. The Item includes the vertical response of an
\naeroplane to a simple discrete sharp-edged gust, extension of this
\napproach to accommodate the delays due to the build-up of lift and
\nincidence and the further extension to a two degree-of-freedom
\nmodel to provide lift and pitch response. Aeroplane response to
\natmospheric turbulence is provided through the relation between the
\nfrequency response function of an aeroplane and the methods of the
\npower spectral density of a random variable.<\/p>\n

The basic equations for the lift and normal acceleration on an
\naeroplane due to the simple sharp-edged gust, that is assumed
\ninstantaneously to change the velocity and angle of incidence of
\nthe aeroplane, are developed. The equations are extended to
\novercome the restrictive nature of an infinite gust gradient by
\nintroducing a gust alleviation factor that also accommodates for
\nthe lag effects of the build-up of lift in response to gust entry
\nand sudden changes of incidence. The analysis is further extended
\nto cover two degree-of-freedom motion in pitch and plunge. The gust
\ndesign criteria for the purposes of satisfying airworthiness
\nrequirements are presented.<\/p>\n

Continuous atmospheric turbulence is assumed to be a stationary
\nrandom process and so the results of power-spectral analysis,
\ndependant upon a scale length and an intensity or standard
\ndeviation of the turbulence, can be applied to the analysis of gust
\nloads on aeroplanes. The general relationship for linear systems
\nbetween the power spectrum of a random input variable and an output
\nresponse are used to relate the spectrum of aeroplane loads to the
\nspectrum of atmospheric gust velocity. For the case of aeroplane
\noutput loads having a normal or Gaussian distribution, as the
\nstandard deviation is used to describe the probability distribution
\nof aeroplane loads. In order to assess the probability of the
\nhighest peak within a time interval or the number of peaks expected
\nin a time interval, frequency of exceedance data methods provide an
\nalternative to cumulative probability methods. Airworthiness
\nrequirements for aeroplanes subject to continuous turbulence are
\ndescribed using the power spectral method and the frequency of
\nexceedance method.<\/p>\n

The methods presented provide a fairly simplistic approximation
\nto realistic atmospheric disturbances, both for discrete gusts and
\nfor turbulence, however they do provide a satisfactory means by
\nwhich representative aeroplane loading can be estimated and
\ncertification satisfied.<\/p>\n

Appendix A presents a brief review of random variable theory
\nintroducing a description of the Fourier series and integral,
\nintroduction of the power-spectral density function and its
\nrelationship to the properties of stationary random processes
\nincluding the mean, standard deviation and auto-correlation
\nfunction.<\/p>\n

The relatively new statistical discrete gust method, which is a
\nway to describe the more extreme gusts in a spectrum, is outlined
\nin Appendix B. This method, which does not form part of the
\nairworthiness requirements, caters for gusts within the high
\nfrequency range of the spectrum, involves aeroplane responses in
\nthe time domain and uses sequences or families of discrete vertical
\ngusts to formulate the probability of occurrence of a given
\nsequence of gusts.<\/p>\n","protected":false},"excerpt":{"rendered":"

An Introduction to Rigid Aeroplane Response to Gusts and Atmospheric Turbulence<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
ESDU<\/b><\/a><\/td>\n2010-06<\/td>\n44<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":0,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2675],"product_tag":[],"class_list":{"0":"post-557327","1":"product","2":"type-product","3":"status-publish","5":"product_cat-esdu","7":"first","8":"instock","9":"sold-individually","10":"shipping-taxable","11":"purchasable","12":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/557327","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=557327"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=557327"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=557327"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}