# Aerodynamic Characteristics of Supersonic Rocket-Sled Involving Waverider Geometry
## 1 Introduction  
In recent years, the study of supersonic and hypersonic flows in the aerospace field has attracted the attention of numerous research institutions. Many countries have begun to focus on theoretical and experimental high-speed flow research, as reflected, for example, in the National Hypersonic Foundational Research Plan (NHFRP) [1]. The development of high-speed aircraft requires extensive tests to validate new theoretical ideas and technologies. However, conventional indoor tests, such as wind tunnel tests, are unable to accurately simulate the real working conditions of the tested device due to missing elements in dynamic performance data. In outdoor free-flight tests, it is difficult to guarantee the conditions of each test, and the test data obtained is quite limited. There is an urgent need for a large dynamic ground test device. The rocket-sled test system meets this need and is becoming more and more important in the field of high-speed testing worldwide. The rocket-sled test system uses a rocket engine as the power unit which causes the rocket-sled test platform to slide along the high-precision track at high speed [2]. The rocket-sled test system has the advantages of both wind tunnel tests and free-flight tests. The carrying capacity, movement speed, acceleration and test environment are easy to control. In addition, the rocket-sled test system is not limited by the size and mass of the test, facilitating observation of the test process and collection of test data. Therefore, the rocket-sled test system has strong practical value and development potential, and can be applied to the aerodynamic testing of airborne equipment (e.g., ejection system, parachute, power system) and material research. The United States was the first country to build supersonic rocket-sled test equipment. It designed and built more than twenty tracks for rocket-sled tests, the most notable track being the Holloman High-Speed Test Track (HHSTT) [3]. The United States has carried out a number of experiments based on this track, and its researchers have put forward many rocket-sled system theories based on experimental data obtained. The development of rocket-sled test systems in China occurred relatively late. In 1993, the first rocket-sled was built in Xiangyang, Hubei province. As a result of development of an expansion project for this high-precision rocket-sled, the length of the sled test system was extended to more than 6000 m--sufficient for further testing of a supersonic rocket-sled. In this paper, the supersonic rocket-sled model is based on this prototype, with a somewhat simplified shape. In supersonic rocket-sled research, real tests are more reliable. [PERSON] et al. [4] conducted several tests on three kinds of supersonic rocket-sleds and compared the results with data from wind-tunnel testing. They found that the aerodynamic force was a primary reason for tension changes. [PERSON] et al. [5] analyzed the pressure distribution on the surface of the sled body of a monorail supersonic rocket-sled and confirmed that ground testing of the rocket-sled could simulate the flight environment of low-altitude aircraft and obtain credible test results. It has been unfortunate that the whole process of supersonic rocket-sled testing has taken so long. From the design of the test process to the preparation of the test device, the consumption of time and material resources has been quite high. In recent years, with the continuous development of computer technology, the computational fluid dynamics (CFD) method has been gradually developed and improved by researchers. It has been widely used in aerospace and other fields. The advantage of the CFD method is that it can collect rich flow information and obtain desired parameters very quickly. CFD can be used to coordinate and guide tests, effectively reducing the number of tests and thus significantly reducing costs. [PERSON] et al. [6] have provided a very detailed and inspiring report on the future application of CFD in aerosciences.