Aerodynamics of a double element wing in ground effect

Abstract

An investigation of a cambered, double-element, high-lift wing operating in ground effect was performed. The effect of ground proximity and ap setting was quanti ed in terms of aerodynamic performance and off-surface ow eld characteristics. From that, it was found that the ow is three-dimensional toward the wing tip with the main element generating most of the downforce but retains quasi-two-dimensional features near the center of the wing. However, at large heights the downforce increases asymptotically with a reduction in height. Then there is either a plateau, in the case of a low ap angle, or a reduction in downforce, in the case of a large ap angle. The downforce then increases again until it reaches a maximum and then reduces with decreasing height above the ground. The maximum downforce is dictated by gains in downforce from lower surface suction increases and losses in downforce caused by upper surface pressure and lower surface suction losses, with a reduction in height. For the high ap angle there is a sharp reduction just beyond the maximum, mainly because of the boundary layer separating, and a resultant loss of circulation on the main element.

Characteristics of Boundary-Layer Transition and Reynolds-Number Sensitivity of Three-Dimensional Wings of Varying Complexity Operating in Ground Effect

“…Downforce and drag curves for the multi-element wing at given in Figure 4. These curves appear similar in shape and trend to those found for a double-element wing (with different profiles to the one used in this study) by Zhang & Zerihan [17]. At higher ground clearances (h/c > 0.3) is the force-enhancement region with concentrated tip-vortex cores [18].…”

Ground-induced lift enhancement in a tandem of symmetric flapping wings: Lattice Boltzmann-immersed boundary simulations

“…An interesting aspect worth to be investigated is represented by the force enhancement induced by the presence of a solid surface, as the ground [24]. For example, the ground effect involving wings composed of single and double elements has been investigated in [25,26], respectively, while the aerodynamics of Gurney flaps has been dissected in [27], showing that the presence of the ground can considerably modify the dynamics of a flapping wing. Motion control, structural design and materials involving the technology of the wing undergoing the ground effect has been reviewed in [28], by devoting with special attention for the mathematical modeling.…”

CFD Investigation of the Effect of the Salient Flow Features in the Wake of a Generic Open-Wheel Race Car

“…The front wing contributes around 30-35% of the overall car downforce [7]. Downforce generated by an inverted wing will increase when in ground effect relative to freestream [8,9,10]. As the ground is approached downforce increases until a critical ride height, beyond which downforce abruptly reduces as stall occurs.…”