LAMINAR SUCTION EXPERIMENTS ON A HIGHLY SWEPT TAPERED WING AT MACH 2.0 AND 2.25.
Final technical rept. Apr 63-Apr 67,
NORTHROP CORP HAWTHORNE CA NORAIR DIV
Pagination or Media Count:
A tapered and highly swept suction wing was designed for and tested in order to determine the feasibility of maintaining laminar flow on such a wing. The 75 deg leading edge sweep and 64 deg trailing edge sweep angles are well in excess of the wave angles at Mach 2.0 and were selected so that the wing could be operated at positive lift with a subsonic type flow having a minimum of generated shocks. To accomplish this the small perturbation theory was employed to determine a camber shape and select a thickness distribution that would result in isobars lying along constant percent chord lines and perpendicular velocity components that were everywhere sub-critical less than local sonic velocity. The suction requirements for laminar flow were calculated and appropriate suction slots were designed for the model. Control of the isobars at the wing root was accomplished by mounting the wing on a contoured plate which simulated a constant chord extension of the wing. Test results showed that the sweep angle of the isobars was quite satisfactory and that the flow appeared to be shockless at 0.0 deg angle of attack the design can be correct at only one angle. The pressure gradients along the wing chord were greater than calculated, however, and this is an undesirable result. A few of the test results showed that laminar flow could be achieved over most of the test area under certain conditions, but because of the steep adverse pressure gradients this accomplishment required high suction and was limited to the lower unit Reynolds number range. Laminar flow was easier to obtain at the roor than at the tip, and the drag coefficient was always highest at the tip.
- Fluid Mechanics