The goal of the project is to simulate and analyze the near C-130 Hercules flow field and then evaluate the influence of passive and active flow control method. This carrier aircraft has been extensively used and is essential while cargos, troops or material supplies has to be delivered rapidly in difficult access areas to military troops or during disasters that require humanitarian supply.
The upsweep region in the aft fuselage leads to an increased drag, due to the highly detached flow and to strong upsweep vortices. The latter can be dangerous, by several means, during airdrop operations. For instance parachutes, while caught on the upsweep vortices can touch the empennage if they exit from the rear door. A good knowledge of the flow pattern around the aircraft is thus of particular interest to be able to control this flow by, for instance, attenuating the upsweep vortices. The ultimate goal of control device is to cancel any undesirable effect in the aft fuselage and enhance airdrop capability.
In this sense it was proved that the aft fuselage region is the site of highly complex flow. Indeed this region is characterized by a massive separation, highly three-dimensional, where one can observe a pair of counter-rotating vortices also called upsweep vortices. These vortices then interact with the lower side of the empennage and cause the flow to detach resulting in counterrotating vortices also called induced vortices.
Author: Bennani, Patrick