Numerical investigation of tangential blowing over the rudder of a vertical tailplane

  • A. GebhardtEmail author
Original Paper


Tangential blowing over the shoulder of a deflected rudder is applied on a vertical tailplane. For a large rudder deflection angle and without blowing the flow is mostly separated on the rudder. Three configurations are investigated in a numerical study with the aim to increase the side force coefficient. The first one is the baseline without blowing, the second one has a continuous full span slot and for the third one discrete slots are used. With sufficient blowing through the continuous slot the separation on the rudder can be removed completely while the separation extent is greatly reduced when using discrete slots. This is investigated for different sideslip angles. An approximately linear increase in the side force coefficient can be found until a sudden side force breakdown occurs. In a further study, the jet blowing velocity is varied. A smaller jet velocity leads to a smaller increase in the side force coefficient. Comparing the continuous and discrete slot configurations shows that for a similar increase in the side force coefficient a much smaller mass flow rate is needed for the discrete slots. However, for jet velocities below the sonic speed the increase in the side force coefficient is limited. It can only be increased by a larger slot extent in spanwise direction but this comes at the expense of an increase in the required mass flow rate.


Vertical tail VTP Active flow control CFD Tangential blowing Discrete slots 



This work is part of the collaborative research project AsSaM (Autoritätssteigerung von Steuerflächen durch aktive Maßnahmen), funded by the German Bundesministerium für Wirtschaft und Energie (Federal Ministry for Economic Affairs and Energy) (Grant no. 20E1513C), which is gratefully acknowledged.


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Copyright information

© Deutsches Zentrum für Luft- und Raumfahrt e.V. 2019

Authors and Affiliations

  1. 1.German Aerospace Center (DLR), Aerodynamics and Flow TechnologyBrunswickGermany

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