Numerical Simulation of Ground Effect on Circulation Control Airfoil

Abstract

Circulation control (CC) is used extensively to control the attitude of rudderless aircraft experiencing ground effect in take-off and landing phases. The investigation of ground effect on airfoil CC is necessary to improve flight performance and quality in proximity to the ground. The aerodynamics and flow field of a modified NACA0012 airfoil with CC in ground effect are investigated with numerical simulations. The compressible Reynolds-averaged Navier–Stokes equations with the shear-stress transport k − ω turbulence model equations are solved using the Finite Volume Method (FVM). Simulation results show that the ground effect changes the lift increment per unit jet momentum coefficient, and CC can reverse the polarity ground effect. The effective angle of attack α E and the downwash space downstream airfoil are altered by the ground effect resulting in variations of airfoil surface pressure and lift. Unlike the unbounded flow field, the jet attachment distance is not only determined by the jet momentum coefficient but it can change with the ride height, which is the distance from the ground to the center of the semicircular Coanda surface, for the same jet momentum coefficient.

Numerical Simulations of Vertical Discrete Gusts Driven by Trailing Edge Blowing

“…In recent years, the circulation control method has been used in many practical situations, benefiting from the precise and effective control capabilities. These situations cover not only flow control or lift enhancement [13,14] but also new applications such as flight control and load alleviation [15,16]. With the development of unsteady trailing edge blowing control methods [17], researchers designed a new type of gust generator based on the concept of circulation control, to avoid unacceptable vibration in the wind tunnel structure and achieve precise control of gust characteristics.…”