\n\tESDU 90029 provides information to assist in the application of
\nthe group of ESDU data on the prediction of the drag due to such
\nexcrescences as grooves, ridges and steps, rivets, and cylinders
\nand stub wings immersed in the boundary layer. Those data were
\nobtained from wind-tunnel tests of an idealised condition in which
\nthe excrescence was mounted on a flat plate with no pressure
\ngradient, and the application of such data to the real aircraft
\nsituation is considered. Corrections are required for the effect of
\npressure gradient and flow orientation. The pressure gradient
\ncorrection on a lifting surface is a magnification factor (although
\nit can be less than unity) and its estimation in incompressible
\ntwo-dimensional flow is discussed; its variation with the
\nboundary-layer parameters on an aerofoil is illustrated
\ngraphically. The analysis is extended to compressible flow and
\nreference is made to the prediction methods of ESDU 87004, 91028
\nand 91029. The treatment of an excrescence only partially immersed
\nin the boundary layer is also considered, and recommendations are
\nmade for the case of excrescences on non-lifting components. The
\neffect of flow orientation is more briefly discussed, and
\nsuggestions are made for some situations, while the treatment of an
\nexcrescence for which no specific data are available is also
\nconsidered. The significance of the excrescence drag penalty on
\naircraft performance is discussed, and acceptable levels in current
\ngood design practice are suggested. Reference is made to ESDU 93032
\nin which the excrescence drag of the wing of a subsonic transport
\naircraft at the cruise condition is considered as a detailed set of
\nexamples in which the data from a number of Data Items are
\nutilised.\n\t<\/p>\n","protected":false},"excerpt":{"rendered":"
An introduction to aircraft excrescence drag<\/b><\/p>\n\n\n
\n Published By<\/td>\n Publication Date<\/td>\n Number of Pages<\/td>\n<\/tr>\n \n ESDU<\/b><\/a><\/td>\n 2012-03-01<\/td>\n 22<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":559009,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2675],"product_tag":[],"class_list":{"0":"post-558998","1":"product","2":"type-product","3":"status-publish","4":"has-post-thumbnail","6":"product_cat-esdu","8":"first","9":"instock","10":"sold-individually","11":"shipping-taxable","12":"purchasable","13":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/558998","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:featuredmedia":[{"embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media\/559009"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=558998"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=558998"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=558998"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}