Body freedom flutter ground test of flying wing aircraft

The flying-wing aircraft has a high short-period modal frequency, which is prone to coupling with the low-order elastic modes of the structure, thereby causing the body freedom flutter. In response to the shortcomings of the current body freedom flutter test methods, a ground flutter test method for the flying-wing aircraft is proposed. Through the coordinated excitation of multiple vibration exciter to simulate the unsteady aerodynamic forces of the rigid body and elastic modes of the structure, the ground test for the body freedom flutter is realized. A reconstruction method for the unsteady aerodynamic influence coefficient matrix of the rigid-elastic coupling based on the hybrid modeling of Computational Fluid Dynamics (CFD) and panel method is established, which can consider the effects of the aircraft thickness and other factors. In addition, this method's calculation efficiency is comparable to that of the panel method, meeting the requirements of body freedom flutter analysis and ground tests. The ground test system was built and tests were carried out for the airplane model. The comparison of the ground test results with the flight test results shows that the flutter boundary and flutter modality are in good agreement, proving the feasibility of this technology in the field of rigid-elastic coupled aeroelasticity.