Date of Award
Master of Science
Department of Aeronautics and Astronautics
Michael M. Walker, PhD
The effect of passive and active boundary-layer fences (BLFs) on performance is evaluated on a NACA 0012 delta wing (croot = 14in, ctip = 2.8in, Λ = 45°, b = 23.5in) at a Reynolds number (Re) of 5.0 x 105 based on the root chord. The performance improvements of a passive BLF are replicated and improved upon using an active flow control (AFC) fluidic fence created by a wall-normal steady-blowing jet from a slot. The application of a passive BLF at a spanwise location of 70% z/b resulted in an 8.7% increase in CLmax compared to the baseline, with no destabilizing pitch moment characteristics and no significant change in angle of attack where stall occurs. The application of an AFC slot operating from Cµ = 0.49% to 12.22% resulted in an increase in CLmax ranging from a 9.7% to 60.3% respectively and no destabilizing pitch moment characteristics. The blowing configuration Cµ = 0.49% resulted in an early onset stall of -2.4°, while the configurations operating from Cµ = 1.95% to 12.22% resulted in a delay of stall between 0.7° to 8.0° angle of attack respectively. This replication will allow for significant performance benefits at higher angles of attack (with AFC turned on), while still allowing for efficient performance at lower angles of attack (with AFC turned off). Aerodynamic performance was assessed by comparing global forces (lift, drag, and pitching moment) measured via a six-component load cell. Surface ow visualization was assessed with long exposure photos of fluorescent tufts under a black light. Overall, active ow control in the form of steady, slotted blowing is shown not only to replicate, but also to improve upon the performance gains of a passive BLF.
Demoret, Anna C., "The Effect of Passive and Active Boundary-layer Fences on Delta Wing Performance at Low Reynolds Number" (2020). Theses and Dissertations. 3213.