Wing/canard interference of a close-coupled canard configuration in static ground effect

The aerodynamics and flow physics of a close-coupled canard configuration W40C60 (the sweep angles of the wing and canard are 40° and 60°, respectively) with sharp leading edge at the angle of attack of 12.0° in static ground effect are investigated by the Delayed Detached Eddy Simulation grounded on Spalart-Allmaras turbulence model. With the ride height decreasing, the lift, drag, nose-down pitching moment and lift to drag ratio of W40C60 increase nonlinearly. In the unbounded flow field, both the canard lift increment and the wing lift decrement due to Wing/Canard Interference (WCI) stem mainly from the leeward surface. With the ride height decreasing, the canard lift increment due to WCI will increase and the wing lift decrement due to WCI will decrease, which is because both the canard and wing windward surface lift increments due to WCI increase significantly with the decreasing ride height. The windward surface lift behaviors are also interpreted as that the windward surface pressure increment of canard and wing of W40C60 due to ground effect is larger than that of the canard alone and the wing alone, respectively. This is because the WCI increases the effective chord length so that the effective dimensionless ride height of W40C60 is smaller than those of the canard alone and the wing alone at the same nominal dimensionless ride height.