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TitleAerodynamics of the Maple Seed
AuthorDesenfans, Philip
ContributorScholz, Dieter
PublisherAircraft Design and Systems Group (AERO), Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences,
CoverageHamburg, Germany
TypeText; Project; doc-type:text; doc-type:studyThesis; info:eu-repo/semantics/report; status-type:publishedVersion; info:eu-repo/semantics/publishedVersion
RightsCopyright by author
Subject(s)ddc:620; info:eu-repo/classification/ddc/629.13; Aerodynamik; Ahorn; Auftrieb; Strömungsabriss; Aerodynamics; Maple; Lift (Aerodynamics); Stalling (Aerodynamics); Aerodynamisches Profil; Anstellwinkel; Freier Fall; Bergahorn; Samen; Evolutionsbiologie; Aerofoils; Angle of attack (Aerodynamics); Acer pseudoplatanus; Seeds; Evolution (Biology); Blade Element Momentum Theory; BEMT; free fall; post-stall; chord; twist; camber; autorotation
Abstract Purpose - The paper presents a theoretical framework that describes the aerodynamics of a falling maple (Acer pseudoplatanus) seed. --- Methodology - A semi-empirical method is developed that provides a ratio stating how much longer a seed falls in air compared to freefall. The generated lift is calculated by evaluating the integral of two-dimensional airfoil elements using a preliminary falling speed. This allows for the calculation of the definitive falling speed using Blade Element Momentum Theory (BEMT); hereafter, the fall duration in air and in freefall are obtained. Furthermore, the input-variables of the calculation of lift are transformed to require only the length and width of the maple seed. Lastly, the method is applied to two calculation examples as a means of validation. --- Findings - The two example calculations gave percentual errors of 5.5% and 3.7% for the falling speed when compared to measured values. The averaged result is that a maple seed falls 9.9 times longer in air when released from 20 m; however, this result is highly dependent on geometrical parameters which can be accounted for using the constructed method. --- Research limitations - Firstly, the coefficient of lift is unknown for the shape of a maple seed. Secondly, the approximated transient state is yet to be verified by measurement. --- Originality / Value - The added value of this report lies in the reduction of simplifications compared to BEMT approaches. In this way a large amount of accuracy is achieved due to the inclusion of many geometrical parameters, even though simplicity is maintained. This has been accomplished through constructing a simple three-step method that is fundamental and essentially non-iterative.