scholarly journals Ballistic Range Testing Data Analysis of Tianwen-1 Mars Entry Capsule

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Haogong Wei ◽  
Xin Li ◽  
Jie Huang ◽  
Qi Li ◽  
Wei Rao
Keyword(s):  
Dynamic Instability ◽  
Linear Regression Method ◽  
Ballistic Range ◽  
Mass Properties ◽  
Testing Data ◽  
Supersonic Regime ◽  
Range Testing ◽  
Mach Numbers ◽  
Scaled Models ◽  
Range Test

A typical blunt body such as Tianwen-1 Mars entry capsule suffers dynamic instability in supersonic regime. To investigate the unstable Mach range of flight and to confirm the design of aerodynamic shape and mass properties, a ballistic range test was carried out aiming at capturing supersonic dynamic characteristics of Tianwen-1. Aerodynamic coefficients of free-flight scaled models were derived by modified linear regression method based on position and attitude data, while the dynamic coefficients were established under the assumption of small angle linearization. The static moment coefficients and dynamic derivatives were identified thereafter. Results show that models in untrimmed configuration are dynamically unstable at certain Mach numbers, whereas models in trimmed configuration are dynamically stable at other Mach numbers tested. Both trimmed and untrimmed configurations are statically stable in all testing cases.

Global Pressure and Temperature Measurements of Ballistic-Range Testing by PSP and TSP Techniques

2014 ◽  
Author(s):  
Hirotaka Sakaue ◽  
Yoshimi Iijima ◽  
Yuki Yamada ◽  
Takeshi Miyazaki ◽  
Masato Ishii
Keyword(s):  
Temperature Measurements ◽  
Ballistic Range ◽  
Range Testing ◽  
Global Pressure

Development of an RF induction plasma generator for ballistic range testing

2000 ◽  
Author(s):  
Heard Lowry ◽  
Les Crosswy ◽  
Joel Mansfield ◽  
Dennis Keefer ◽  
Monty Smith ◽  
...  
Keyword(s):  
Plasma Generator ◽  
Induction Plasma ◽  
Ballistic Range ◽  
Range Testing ◽  
Rf Induction Plasma

scholarly journals Designing a Control System for an Airplane Wing Flutter Employing Gas Actuators

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
A. R. Ansari ◽  
A. R. B. Novinzadeh
Keyword(s):  
Good Accuracy ◽  
Dynamic Instability ◽  
Pulse Frequency ◽  
Primary Control ◽  
Wing Flutter ◽  
Supersonic Regime ◽  
Process Output ◽  
Gas Consumption ◽  
Airplane Wing ◽  
Layer Flow

The wing flutter is a dynamic instability of a flight vehicle associated with the interaction of aerodynamic, elastic, and inertial forces (aeroelastics phenomena). In this study, just the primary control is investigated. Also, in order to control the two-dimensional wing flutter, the force jet and pulse width pulse frequency (PWPF) are suggested. The PWPF modulator has the advantage of almost linear operation, low jet gas consumption, flexibility in addressing various needs, and good accuracy in presence of oscillations. This scheme makes use of quasi-steady dynamic premises and incompressible flow, as well as the thin airfoil theory. It should be noted that, to justify the application of the aerodynamic theory, we have speculated that the thruster jet ejected through a nozzle with a diameter smaller than several millimeters has a supersonic regime (with Mach number of the order of M≈3.5). Consequently, the interference of the thruster jet in the boundary layer, flow, and circulation around the airfoil which are characterized by low speed would be negligible. The operation of the jet as a thruster is handled by the PWPF modulator, and the process output is fed back to the system via a PD controller. In order to control the wing flutter oscillation, the location of installing the actuator on the airfoil is investigated.

Ballistic range experiments on the superboom generated at increasing flight Mach numbers

1976 ◽  
Vol 59 (3) ◽  
pp. 520-524 ◽  
Author(s):  
M. Sanai ◽  
T.‐Y. Toong ◽  
A. D. Pierce
Keyword(s):  
Ballistic Range ◽  
Mach Numbers

scholarly journals Dynamic CFD Simulations of the MEADS II Ballistic Range Test Model

2016 ◽  
Author(s):  
Eric Stern ◽  
Alan Schwing ◽  
Joseph M. Brock ◽  
Mark Schoenenberger
Keyword(s):  
Test Model ◽  
Cfd Simulations ◽  
Ballistic Range ◽  
Range Test

scholarly journals Speed of sound gradients due to summer thermal stratification can reduce the detection range of acoustic fish tags: results from a field study in Hamilton Harbour, Ontario.

2020 ◽  
Author(s):  
Mathew G. Wells ◽  
Jingzhi Li ◽  
Bryan Flood ◽  
Yulong Kuai ◽  
Jill L. Brooks ◽  
...  
Keyword(s):  
Thermal Stratification ◽  
Thermal Gradients ◽  
Short Term ◽  
Detection Range ◽  
Hamilton Harbour ◽  
Key Factor ◽  
Range Testing ◽  
Derived Data ◽  
Internal Seiches ◽  
Range Test

Understanding detection range is a key factor for the use of acoustic telemetry in fisheries research. Lakes have strong seasonal changes in thermal stratification, as well as short-term changes due to internal seiches. These thermal gradients in lakes imply strong sound-speed gradients that can refract and diverge acoustic signals, leading to acoustic attenuation and smaller detection range. Using field-based range testing and the Bellhop acoustic model, we investigated how changes in stratification lead to changes in detection range within Hamilton Harbour, Ontario, Canada. During the summer stratified period, the detection range was less than 350 m, whereas in the isothermal fall, range was up to 500 m. Range test data from three separate field observations showed a good correlation with Bellhop predictions. Due to the intense internal seiches in Hamilton Harbour, the stratification in the shallower littoral regions essentially switched between stratified and isothermal conditions over short timescales, which is predicted to lead to high temporal variability in detection range that must be accounted for during the analysis and interpretation of telemetry derived data.

scholarly journals Shock waves induced by a planar obstacle in a vibrated granular gas

2018 ◽  
Vol 842 ◽  
pp. 163-187 ◽  
Author(s):  
Alexandre Vilquin ◽  
Hamid Kellay ◽  
Jean-François Boudet
Keyword(s):  
Shock Waves ◽  
Shock Front ◽  
Granular Media ◽  
Volume Fraction ◽  
Good Description ◽  
Mean Velocity ◽  
Granular Gas ◽  
Wide Range ◽  
Supersonic Regime ◽  
Mach Numbers

The low value of the speed of sound in dilute granular media permits the study of the properties of supersonic flows for a wide range of Mach numbers. In this paper, we report the experimental observation of a subsonic–supersonic transition in a vibrated granular gas. The shock fronts studied are obtained by simply pushing a rectangular obstacle into the granular gas for different obstacle velocities. The supersonic regime is characterized by the formation of normal shock waves whose width increases when the Mach number decreases to values close to 1. The bimodal model proposed by Mott-Smith in the 1950s provides a good description for the velocity distributions as well as the macroscopic quantities for shock waves in molecular gases but remains inadequate for dissipative media like granular gases and plasmas. Here by examining the shock front structure for a wide range of Mach numbers, we adapt the Mott-Smith bimodal description to a dissipative medium. By using balance equations from granular kinetic theory and taking into account different dissipation sources, the proposed model allows us to understand how this dissipation modifies temperature, mean velocity and volume fraction profiles through the shock front.

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