Prediction and Validation Technologies of Aerodynamic Force and Heat for Hypersonic Vehicle Design

The aerodynamic characteristics of a hypersonic aircraft determine its trajectory and performance of flight, and the aerodynamic characteristics are impacted by the contour of the hypersonic aircraft.

The conditions of flight environment for hypersonic aircrafts are all airspace and large velocity field. It is necessary to develop an environment prediction and verification method with high precision that comprehensively considers various physical effects under real flight conditions as ground design is difficult to fully simulate the high-altitude environment and flight conditions.

As a non-streamline body, bluff body is widely applied in many engineering projects such as aerospace, construction, transportation, and environment, which has a larger and even more overwhelming differential pressure resistance compared to streamlines in case of aircraft, building structures, bridges, automobiles, heat exchangers, eddy-current flowmeter, etc., and is a classic branch in the research field of fluid mechanics. There are rich passing flow structures around the bluff body. For example, the surface of the bluff body will generate a wide range of boundary layers of separation and form a wide wake flow with vortex shedding.

The aerospace industry has experienced more than 100 years of development since the birth of the aircraft in 1903, and mankind have created milestones one and another in the history of flight. Basic theories, testing methods, and calculation methods on flight have been gradually developed and improved with the development of the times and industry, which have always played an irreplaceable role in opening up one new era after another for incompressible subsonic velocity, compressible subsonic velocity, transonic velocity, and supersonic velocity.

As a common flow phenomenon in nature, turbulent flow is often accompanied by flow transition. Turbulent/transitional flow exists widely in fluid machinery, which is developed and utilized by people to serve their life in cycle. For example, the boundary layer flow of the wing and fuselage will often change from the laminar state to the turbulent state when various aircraft are on flights, which has a serious impact on the lift and drag of the aircraft and even the aerodynamic heating. The boundary layer flow will also change from laminar flow to turbulent flow for the blades in various rotating machines, which will have impact on the efficiency of the impeller. Therefore, it is very essential for the prediction on turbulent/transitional flow. Researchers have worked out a variety of numerical prediction methods for turbulent/transitional flow at present, including LST stability analysis methods, DNS or LES high-precision finery simulation methods, numerical prediction on turbulent/transitional flow model methods and various engineering experience criteria, etc., which have different predictive capabilities in practical applications. Research will be carried out on these methods to analyze their capabilities.

As a comprehensive measurement system, the atmospheric data system processes and calculates other parameters related to atmospheric data, such as barometric altitude, height deviation, lifting speed, true airspeed, indicating airspeed, Mach number, rate of change of Mach number, atmospheric density ratio, etc., based on the basic raw information measured by the sensors, such as static pressure, dynamic pressure, angle of attack, and total temperature, which will be sent to flight control system, navigation system, engine control system and flight data recording system that is one of the necessary avionics subsystems for various aircraft.

The technology on non-contact measurement of wind tunnel is a new and advanced optical measurement technology. It has the advantages of non-contact, unchanged model contour, high precision, high resolution and high measurement efficiency, compared with traditional technology of sensor point measurement. The development of aircraft design requires wind tunnel tests to provide more accurate and comprehensive data. The technology on non-contact measurement of wind tunnel can not only improve data accuracy, but also improve test efficiency. It is an important development direction in the field of wind tunnel testing in the future.