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.
| Identifer | oai:union.ndltd.org:haw-hamburg.de/oai:Desenfans |
| Date | January 2019 |
| Creators | Desenfans, Philip |
| Contributors | Scholz, Dieter |
| Publisher | Aircraft Design and Systems Group (AERO), Department of Automotive and Aeronautical Engineering, Hamburg University of Applied Sciences, |
| Source Sets | Hamburg Universtiy of Applied Sciences (HAW Hamburg) |
| Language | English |
| Detected Language | English |
| Type | Text, Project, doc-type:text, doc-type:studyThesis, info:eu-repo/semantics/report, status-type:publishedVersion, info:eu-repo/semantics/publishedVersion |
| Format | text/html |
| Coverage | Hamburg, Germany |
| Rights | Copyright by author, CC BY-NC-SA, https://creativecommons.org/licenses/by-nc-sa/4.0, info:eu-repo/semantics/openAccess |
| Relation | Digital Library - Projects & Theses - Prof. Dr. Scholz, http://library.ProfScholz.de |
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