高重复频率激光能量沉积减小超声速波阻的数值研究

Numerical analysis of supersonic drag reduction with repetitive laser energy deposition

采用数值模拟的方法研究了激光重复频率、点火位置及来流马赫数等参数对激光能量沉积减小超声速钝头体波阻的影响。数值模拟结果表明,由于激光能量的沉积产生的低密度区与弓形激波相互作用,在钝头体前形成了类似虚拟尖锥的回流区,使原弓形激波逐渐向阻力较小的斜激波转变。阻力随着频率的增加而减小,当频率增加到200 kHz时,阻力减小到约为原来的17%,能量效率的最大值出现在频率为50 kHz处。说明控制参数的选择对减阻性能起着关键的作用。

Numerical simulations have been conducted to study wave drag reduction over a cylindrical blunt body with repetitive laser energy deposition.The influences of laser repetition frequency,inflow Mach number and ignition location on drag reduction performances were investigated.Because of the interaction between low density zone caused by laser energy deposition and bow shock wave over the cylinder,a circulation zone similar to virtual tip is formed in front of the blunt body.And the energy deposition modifies the upstream shock wave into an oblique one and results in large wave drag reduction.With the laser repetition frequency increasing the drag reduces： At the frequency of 200 kHz,the drag is reduced to as low as 17% of that without energy deposition,and the maximum energy efficiency appears at the frequency of 50 kHz.Thus it is very important to choose proper control parameter in supersonic drag reduction.