A Survey of Application and Development of Small Disturbance Equation Method in the Aviation Area

All the small disturbance equation (SDE) methods, which are a useful technique to enhance the stability and security of the aircraft, play a significant role in the development of the aviation area. This review paper briefly introduces the development of the SDE and summarizes the two calculation methods combining with the SDE and application of the SDE method in the aviation area. The calculation methods mainly focus on the approximate factorization (AF) algorithm with the SDE and Newton-Orthomin method with the SDE. AF algorithm with the SDE is robust enough, and it can choose the calculation methods according to accuracy rather than stability that significantly saves the calculation cost. The newton-Orthomin method with the SDE can improve computing efficiency by 2.1 to 4.5 times compared with the monotone AF method. The direction of application focus on the flutter analysis, gust analysis and resizing of some component in the aircraft and the disadvantages are explored for each type. In conclusion, the combination of the SDE with the other algorithms can increase calculation efficiency, and the SDE has a wide range of applications in the aviation area. This paper can provide relevant references for the subsequent combination of the SDE and other algorithms development or practical application of SDE.