Investigation Of The Continuous Scan Techniques In Engineer To Aircraft In Low Speed Wind Tunnel

No matter the army aircraft or common aircraft, it is necessary to do a lot of force tests in wind tunnel for their investigation and remodeling. For the high capability battleplane, the variety of aerodynamic characteristic before and after the stall when flying with high attack angle must be studied, and for the big aerotransport, the attack angle at the stall point and the minimum resistance must be obtained. The step-advanced-angel test means can not deal with these problems now, meanwhile, it will, in some way, delay the process and periods for its low efficiency and long testing time. Continuous scan test is a kind of force test technology that can get the serried aerodynamic characteristic data in the process of model gesture changing uniformly. So it will have important significance to improve this technology for engineering application, in which a lot of subtle aerodynamic data can be obtained, and the efficiency of the force tests in wind tunnel can be increased.Based on the research of the test technology at home and abroad, the key technical issues in contact with this work are analyzed. The new method of data noise reducing aimed at the aerodynamic law and noise characteristic of the original data in wind tunnel test is proposed in the purpose of eliminating the noise signal in the data. The accurate measurement of model attack angle is researched, and the error caused by model vibration acceleration and angular velocity in measuring the attack angle is eliminated. It can establish a solid foundation for continuous scan test technology and the engineering application.In order to achieve the effective de-noising of test data, the theory of Wavelet de-noising is used. The characteristic of de-noising is validated by numerical emulation and wind tunnel test, the Wavelet de-noising function and high frequency modulus threshold are confirmed, the noise is separated from the test data well and truly. By designing the control project and optimizing the control parameter, the measured error of attack angle caused by vibration acceleration is restrained. By error analyses, the measured error of attack angle produced by model angular velocity is corrected. On the base of these work, the test project is designed, all applications program required by test are developed, the continuous scan force tests of a certain plane are accomplished, and the test data are compared with that of general force tests, the conclusion that continuous scan test data satisfy the precision request of national military standard is obtained, the test efficiency can increase 30% compared with that of the general force tests.At present, the continuous scan test technology has been successfully used in many force tests of key weapon such as Yun-8 aircraft. The research results in this paper about continuous scan test technology have been prepared for applying to other large-scale wind tunnel.