Characteristic features of low-temperature gas-discharge plasma flows

Weakly ionized plasmas in aerospace applications

“…In principle, the observed difference could be ascribed to a higher sonic velocity in plasma, but the physical mechanism of the effect was unclear. The interest in these experiments increased considerably in the 1980s [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and has not weakened until today [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Along with the ballistic experiments [3,5], an intense study of shock tube experiments where a planar shock wave was propagated through a discharge plasma was undertaken [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

“…The interest in these experiments increased considerably in the 1980s [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and has not weakened until today [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Along with the ballistic experiments [3,5], an intense study of shock tube experiments where a planar shock wave was propagated through a discharge plasma was undertaken [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The main effects observed in these experiments can be summarized as follows.…”

“…More detailed study of ballistic experiments allowed also for revealing a reduction of aerodynamic drag force F d for bodies moving in plasma [3,5]. It was found that not only the drag force but also the specific drag coefficient C d = 2F d /(ρU 2 S ⊥ ) changes in plasma (here ρ is gas density, U is the velocity of a moving body, S ⊥ is the area of the body cross-section).…”

Gasdynamic phenomena accompanying the motion of shock waves and objects in a low-temperature nonequilibrium plasma

“…͑1͒ that the velocity of sound in the plasma is a P ϭ1.46aͱT P /T. Estimates made using the change in the separation of the shock wave front in the plasma 12 give a P ϭ1.48aͱT P /T, and those made using the change in the drag coefficient 17 give a P ϭ1.45aͱT P /T. With this in mind, Eq.…”

“…The initial pressure behind the shock waves and the pressure behind the shock waves reflected by the walls is also substantially lower in plasma than in air. 17 This implies that the local loads on an object flying into plasma should be substantially lower than those in normal air. The aerodynamic characteristics of simple objects and the forces acting on them in a plasma may be estimated approximately from results of their measurements in any gas using the conversion relations C X,Y P ϭC X,Y P ¯RP Ј /P ¯R Ј , X P ,Y P ϭ0.5C X,Y P V 2 P ¯RP Ј /P ¯R Ј ,…”