{"id":557419,"date":"2024-11-05T18:17:58","date_gmt":"2024-11-05T18:17:58","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/esdu-080112009\/"},"modified":"2024-11-05T18:17:58","modified_gmt":"2024-11-05T18:17:58","slug":"esdu-080112009","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/esdu\/esdu-080112009\/","title":{"rendered":"ESDU 08011:2009"},"content":{"rendered":"

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

This Data Item is the first in the series of four Items (Parts
\nIIIA to IIID) comprising Part III of the wider five-part series
\n(Parts I to V) dealing with the aerodynamics and aero-acoustics of
\nrectangular planform cavities:<\/p>\n

Part I: Time-averaged Flow \u2013 ESDU 02008 (Reference 31)<\/p>\n

Part II: Unsteady Flow and Aero-acoustics \u2013 ESDU 04023
\n(Reference 32)<\/p>\n

Part III: Alleviation of Unsteady Flow Effects,<\/p>\n

IIIA Introduction \u2013 ESDU 08011 (This Data Item)<\/p>\n

IIIB Acoustic suppression using passive devices \u2013 ESDU 08012
\n(Reference 33)<\/p>\n

IIIC Acoustic suppression using active devices \u2013 ESDU 09001
\n(Reference 34 to be issued)<\/p>\n

IIID Store deployment \u2013 ESDU 09002 (Reference 35, to be
\nissued)<\/p>\n

Part IV: Overview of CFD methods \u2013 Reference 37, (Data Item to
\nbe issued),<\/p>\n

Part V: Bibliography and Tabular Survey \u2013 Reference 38, (Data
\nItem to be issued).<\/p>\n

The general subject area of Part III is the alleviation, or
\nsuppression, of unsteady flow effects and is introduced by the
\npresent Item (Part IIIA). Part IIIB (ESDU 08012) deals with
\nacoustic suppression using passive devices. The use of active
\ndevices is considered in Part IIIC (ESDU 09001), while the
\nimprovement of store deployment conditions is dealt with in Part
\nIIID (ESDU 09002).<\/p>\n

Section 2.1, below, gives general background information behind
\nthe need for the alleviation of weapons bay noise and the
\nimprovement of store deployment conditions, two important problem
\nareas concerning the internal carriage of weapons. It is noted
\nthat, ideally, the means to overcome those problems should not
\nincrease the drag of the aircraft; preferably, it should decrease
\nit.<\/p>\n

The general principles involved in the suppression of the
\neffects of unsteady flow are discussed in Section 3. Sections 3.1
\nand 3.2 consider open or transitional flow and closed flow,
\nrespectively, with particular attention being paid to the possible
\nalleviation strategies.<\/p>\n

Section 4 deals with the classification of devices used to
\ncontrol cavity unsteady flow, whether related to noise or store
\ndeployment conditions. Of the two main categories, passive devices
\nare usually not categorised further. On the other hand, active
\ndevices are commonly categorised as having either open-loop or
\nclosed-loop operation.<\/p>\n

Many of the wind-tunnel tests or CFD simulations involving
\nacoustic suppression devices concern simple rectangular box
\ncavities, often with no doors fitted and usually with no stores
\ninstalled. Therefore, Section 5 presents data giving some idea of
\nthe effects of cavity shaping (Section 5.1), doors (Section 5.2)
\nand stores (Section 5.3) on the noise characteristics of cavities
\nwith no suppression devices. Such material can be used in a number
\nof ways; for example, as a guide to the relative effectiveness of a
\ngiven suppression device in different baseline (i.e. no suppression
\ndevice fitted) situations.<\/p>\n

Section 6 deals with drag considerations in the choice of an
\nacoustic suppression device. The few instances which feature the
\neffect of a suppression device on the drag, in addition to the
\nacoustics, of a cavity are discussed in Section 6.1. In order to
\nunderstand the effect on drag in the assessment of various passive
\ndevices, the concept of cavity baseline drag (gross drag) and its
\nrelationship with the drag (net drag) predicted using ESDU 00006
\n(Reference 29) and ESDU 00007 (Reference 30) is outlined in Section
\n6.2. Finally, the assessment of the installed drag of each of the
\npassive devices dealt with in Sections 3 to 9 of ESDU 08012 is
\nconsidered in Section 6.3.<\/p>\n","protected":false},"excerpt":{"rendered":"

Aerodynamics and Aero-Acoustics of Rectangular Planform Cavities – Part IIIA: Alleviation of Unsteady Flow Effects – Introduction<\/b><\/p>\n\n\n\n\n
Published By<\/td>\nPublication Date<\/td>\nNumber of Pages<\/td>\n<\/tr>\n
ESDU<\/b><\/a><\/td>\n2009-06-01<\/td>\n36<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":557429,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2675],"product_tag":[],"class_list":{"0":"post-557419","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\/557419","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\/557429"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=557419"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=557419"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=557419"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}