Enhancing aircraft control surface effectiveness by co-flow jet flap at low energy expenditure

Abstract

This paper conducts Improved Delayed Detached Eddy Simulation (IDDES) to compare applying co-flow jet (CFJ) active flow control on the flap and on the front main part of an aircraft control surface. Trade studies with varying CFJ momentum coefficients (Cμ) and flap deflection angles (δ) indicate that using CFJ on the flap is much more effective and efficient than applying CFJ on the front main part of the control surface. It is attributed to the feature that CFJ is more advantageous to work in severe adverse pressure gradient (APG). With a small Cμ of 0.025, the configuration with CFJ on the flap achieves a 46.1% increase of lift coefficient (CL) with an 80.8% lower power consumption compared with the one using CFJ on the front part. Moreover, the control surface with CFJ on the flap can attach the flow very well at a very high deflection angle of 70∘ and achieves a CL of 2.5 times larger than that of the baseline control surface.