Continuing evolution of aerodynamic concept development using collaborative numerical and experimental evaluations

Abstract

Traditionally, computational predictions and experimental evaluations of aerodynamic concepts have been conducted separately, with little collaboration other than post priori comparisons of results. This has led to distrust and even antagonism between the computational and the experimental communities. These difficulties probably began when early computational fluid dynamic practitioners boasted that wind tunnels would become sec ondary in aerodynamic concept development within a few short years, a prediction that has not come true. On the contrary, it is believed that a great deal of synergy can be cultivated when computational and experimental evaluations are conducted in an integrative fashion. A variety of projects where this has been done will be reviewed, including a pitching Unmanned Combat Air Vehicle, a delta wing with periodic suction and blowing for aerodynamic control, a missile with drag brakes that caused excessive unsteady flow, a C-130 aircraft configured for airdrop, and closed-loop flow control. Further evolution of the numerical/experimental collaboration will be discussed showing results from the flow control research where the dividing line between numerical predictions and experimental evaluations is becoming blurred. Suggestions for future directions in collaboration will also be made.

Numerical prediction and wind tunnel experiment for a pitching unmanned combat air vehicle

“…They used PIV measurements to quantify the unsteadiness of the wake of the airfoil and found that measurements could not be repeated to desirable levels from one test to another. While this should not keep researchers from performing wind tunnel tests, it does point to the benefits of conducting integrated ex perimental/computational research [7], so that the strengths of each approach can be fortified and the weaknesses of each ap proach can be reduced.…”

Aeronautics and astronautics: Recent progress and future trends

“…CFD simulations provide a vast array of relatively dense data, whereas wind tunnel experiments provide smaller sets of sparsely arranged data, but include the direct measurement of global variables such as lift, drag, or pitching moment. Thence, significant gains can be achieved if both data sources can be combined to provide a more complete picture of the flow field [66,67].…”