Aerodynamic characteristics of a free-flight scramjet vehicle in shock tunnel

Abstract

A multi-component aerodynamic test for an airframe-engine integrated scramjet vehicle model was conducted in the free-piston shock tunnel HIEST. A free-flight force measurement technique was applied to the scramjet vehicle model named MoDKI. A new method using multiple piezoelectric accelerometers was developed based on overdetermined system analysis. Its unique features are the following: (1) The accelerometer’s mounting location can be more flexible. (2) The measurement precision is predicted to be improved by increasing the number of accelerometers. (3) The angular acceleration can be obtained with single-axis translational accelerometers instead of gyroscopes. (4) Through the averaging process of the multiple accelerometers, model natural vibration is expected to be mitigated. With eight model-onboard single-axis accelerometers, the three-component aerodynamic coefficients (Drag, Lift, and Pitching moment) of MoDKI were successfully measured at the angle of attack from 0.7 to 3.4 degrees under a Mach 8 free-stream test flow condition. A linear regression fitting revealed a 95% prediction interval as the measurement precision of each aerodynamic coefficient. Graphical abstract

User Authentication by Gait Data from Smartphone Sensors Using Hybrid Deep Learning Network

“…With the advent of the micro-electro-mechanical system (MEMS) technology, the application of inertial sensors is becoming increasingly mature [12]. Moreover, smartphones, which integrate many advanced inertial sensors, including accelerometers and gyroscopes, are widely used today due to their small size, portability and low power consumption [13][14][15]. Therefore, gait recognition based on smartphones' inertial sensors, in which data are generated by the movement of a walking body, has gradually attracted increasing attention for human identification and verification [16][17][18][19][20][21].…”

Editorial: topical collection on hypersonic flight

“…The contributions of Gülhan et al (2021), Running and Juliano (2021), and Threadgill and Little (2022) concentrate on the important problems of shock-wave/boundary-layer interactions and shock-shock interactions (SSI), while Cardona et al (2021) extend the study of SSI to the rarefied regime. Investigations of the free-flight aerodynamics of single (Seltner et al 2021) and multiple (Whalen and Laurence 2021) bodies, relevant to space debris reentry and meteoroid fragmentation in the atmosphere, are also included in the collection; free-flight experiments on a large scramjet model are documented in Tanno and Tanno (2021).…”