Numerical Investigation of Unsteady Blowing Through Discrete Slots on a Swept Vertical Tail of Infinite Span

Abstract

Active flow control over the rudder shoulder of a vertical tail plane is applied to increase its side force coefficient. The rudder of the infinite span model is deflected. This leads without actuation to separated flow over the rudder. Several investigation are conducted. First a full-span constant blowing slot is used. With sufficient high jet velocity the flow on the rudder can be attached. By using in a next step several discrete slots, the required mass flow rate can be reduced for a similar increase in the side force coefficient. Using then pulsed blowing from the discrete slots is advantageous since the mass flow rate can be reduced. However, this is only true for quite small momentum coefficients. For cases with high side force coefficients requirements only the constant blowing approach is capable to achieve them, albeit at the correspondingly large mass flow rates and momentum coefficients.