Numerical investigation of slot variations on the efficiency of tangential blowing at a vertical tailplane with infinite span

Abstract

On a swept vertical tailplane with infinite span tangential blowing over the shoulder of a deflected rudder is applied. For large rudder deflection angles the flow on the rudder is separated without blowing. A numerical study is conducted with the aim to increase the side force coefficient. This could for example be required during takeoff if the engine on one side fails, necessitating the compensation of a large yawing moment. If this criterion is critical for the sizing of the vertical tailplane, active flow control like tangential blowing could help to reduce the size of the vertical tailplane and thus save weight and fuel. With a continuous slot it is demonstrated that the separation on the rudder can be reduced or avoided. It is shown that by using discrete slots this can be achieved with a smaller momentum coefficient. To analyze the effects of the discrete slots and their jets on each other and their effectivity with regard to the gain in side force coefficient a parameter study is conducted. The number of slots as well as the size of the slots in spanwise direction is varied and the impact of jet velocity changes is also studied. In comparing the results for a constant increase in side force and constant slot size in spanwise direction the configuration with the smaller number of slots but a higher jet velocity proved to be the most effective one.

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

“…The slot height is 0.0006 of the local chord length leading to a relatively thin channel. This height was also used for the preceding investigations with an infinite swept wing [9]. For a middle VTP section this would be a slot height of 0.32mm.…”

“…Therefore the full span slot is divided into several discrete slots with finite width and some gaps without slots between them. The slot width and gap size was taken from a previous investigation of an infinite swept wing with a constant chord [9].…”

Airfoil gust load alleviation by circulation control

“…For example, on top of transition delay and drag reduction, these methods have been proven to be effective to prevent flow separation and augment lift. A wide range of active flow control studies can be found on the subjects of flow mechanism [10,11], comparison of effectiveness of different actuators [12,13], parameter studies including geometry parameters [14], injection or suction parameters [15][16][17] and excitation parameters [18], influence of locations and layouts [19]. Some significant breakthroughs have been achieved using fluidic actuators for improving aerodynamic performance.…”