T. Effing, F. Schueltke, E. Stumpf

The preliminary aerodynamic design of aircraft with integrated hybrid laminar flow technology essentially consists of a reliable and robust transition prediction and the estimation of laminar drag polars under given wing geometry and flow conditions. Using an inhouse developed process chain for laminar flow analysis, the effects of the Reynolds number on various instability mechanisms and the corresponding transition location are derived in this study. With constant design parameters (Mach number, lift coefficient, suction distribution), the destabilization of the boundary layer can be fundamentally attributed to the Reynolds number as a decisive factor. Similar to the theory of a flat plate, a critical Reynolds number is defined, exceeding which leads to an abrupt shift of the transition location. In addition, the influence of varying wing geometry parameters on this critical threshold is investigated. Based on the presented findings, a necessity for extending the existing process chain is derived in order to adequately reflect the influence of the Reynolds number. The advantages of the adapted method are shown in a comparative application example using an Airbus A350-900 preliminary design. By taking the influence of the Reynolds number into account, a considerable increase in prediction accuracy of laminar drag components is achieved. Furthermore, it is briefly discussed that varying the suction distribution can lead to a complete avoidance of above mentioned transition shifts and thus to a significant reduction of laminar drag components.

Deutscher Luft- und Raumfahrtkongress 2018, Friedrichshafen

Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn, 2019

Conference Paper

englisch

21,0 x 29,7 cm, 10 Seiten

urn:nbn:de:101:1-2019011114111135395146

10.25967/480188

Reynolds number, Instability mechanisms, Hybrid laminar flow control, Conceptual aircraft design

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Effing, T.; Schueltke, F.; Stumpf, E. (2019): Investigation of the Influence of the Reynolds Number on the Prediction Accuracy of Laminar Drag Components. Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V.. (Text). https://doi.org/10.25967/480188. urn:nbn:de:101:1-2019011114111135395146.

11.01.2019