On the location of the laser energy deposition region in wave drag reduction

Shock Waves ◽  
2019 ◽  
Vol 29 (7) ◽  
pp. 929-940 ◽  
Author(s):  
R. Joarder
AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 460-467 ◽  
Author(s):  
David Riggins ◽  
H. F. Nelson ◽  
Eric Johnson

AIAA Journal ◽  
10.2514/2.756 ◽  
1999 ◽  
Vol 37 (4) ◽  
pp. 460-467 ◽  
Author(s):  
David Riggins ◽  
H. F. Nelson ◽  
Eric Johnson

2013 ◽  
Vol 437 ◽  
pp. 286-289 ◽  
Author(s):  
Qian Li ◽  
Yan Ji Hong ◽  
Juan Fang ◽  
Dian Kai Wang

Wave drag is high when vehicle flights in supersonic, which impacts on aerodynamic performance of the vehicle heavily, so how to reduce wave drag becomes an important problem which needs to be solved. As an active-controlling technology on flow, drag reduction by laser energy deposition has been paid more and more attention to by researchers. Based on Euler equations, mechanical model and numerical method of drag reduction induced by laser plasma are established. Effect on drag reduction performance of hemispherical blunt body of laser energy, blunt size, temperature and pressure of surrounding gas is studied. A dimensionless energy factor is extracted according to numerical results. Results indicate: drag reduction percentage increases with dimensionless energy factors increasing when dimensionless energy factor is less than 0.7; when dimensionless energy factor is greater than 0.7, energy will reach saturation, and drag reduction percentage keeps constant approximately; power efficiency decreases with dimensionless energy factors increasing. Therefore, similar law of drag reduction performance by laser plasma is obtained preliminarily, which provides possibility for reliable amplification of drag reduction by laser energy deposition.


2009 ◽  
Vol 21 (6) ◽  
pp. 066102 ◽  
Author(s):  
Yousuke Ogino ◽  
Naofumi Ohnishi ◽  
Shinichi Taguchi ◽  
Keisuke Sawada

Author(s):  
Jae-Hyung Kim ◽  
Akihiro Sasoh

Supersonic wave drag reduction due to the repetitive laser induced energy deposition is performed experimentally in this study. Laser pulses are irradiated through a convex lens installed in side of the in-draft wind tunnel of Mach 1.94. The maximum frequency and power of the energy deposition is limited up to 50kHz and 400W. In order to estimate the drag reduction, time-averaged drag force is measured by a force balance system and stagnation pressure history is synchronized with corresponding sequential schlieren images captured by high-speed camera. Drag reduction performance is linearly increased up to 21% with input laser power. The power gain which only depends on the pulse energy, is realized by approximately 7. Virtual spike formation induced by highrepetitive energy depositions is remarkably discussed in the visualization results.


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