Measurement of Aerodynamic Forces and Moments in Wind Tunnels

Abstract

Abstract Aerodynamic forces and moments are among the most important data required for flight vehicle performance simulation and design, and such data can be obtained through wind tunnel model tests among other methods. The work described here relates to wind tunnel tests based on relativity and similarity principles. Test models of the studied objects were fabricated in accordance with similarity criteria and connected to a balance and support system fixed on a motion‐controlling mechanism for changing or controlling the attitude angles of the model. This has been installed in the test section of a wind tunnel. When gas flows under test conditions through the wind tunnel section, aerodynamic forces and moments exerted on the model are transferred to the balance and converted into electrical signals. These signals are filtered and amplified by a signal‐conditioning system, sampled by a data acquisition system and then processed to obtain the aerodynamic forces and moments. Other parameters such as total and static pressures, total temperature, and model attitude angle are measured by a pressure transducer, temperature sensor, and angle sensor, respectively. After synthesizing all the measurements, the non‐dimensional aerodynamic force and moment coefficients are obtained and then used for vehicle design and simulation.