摘要
采用数值方法分析研究强激光束在对流风作用下的热晕效应。湍流数值模拟采用雷诺平均及大涡模拟(RANS/LES)混合方法,即脱体涡方法,同时耦合J-B模型,而利用双时间步进行非定常问题迭代求解;光在流场和自由空间的传输计算采用波动光学方法,并根据远场光斑分布情况进行定性与定量分析。研究考察了0.1 MW功率0、.1 m口径的Gauss光束在1,5和10 m/s对流风作用下的热晕效应。结果表明,对流风作用下的热晕效应是非定常作用过程;对流风速度越低,激光热晕效应越强,其中1 m/s的热晕效应最强,其远场光斑畸变最严重;对流风速度越低,热晕效应非定常作用特性越明显,尤其1m/s的热晕效应在5 s观察时间内仍在发展变化,而5 m/s和10 m/s的热晕效应在3 s以后已趋于稳定。
In this paper,thermal blooming of high power laser affected by the convective wind has been simulated numerically and studied.Turbulences are simulated with the RANS/LES hybrid method,coupled with the J-B model.The duel time steps method is used for solving unsteady flow problems.The wave optics method is adopted to simulate beam propagation through both flow field and free space.Based on far field spot,qualitative and quantitative analysis has been carried out.Thermal blooming of Gauss beam with power of 0.1 MW and diameter of 0.1 m,affected by the convective wind at different velocities as follows 1,5 and 10 m/s,has been investigated.Results show that thermal blooming affected by the wind is unsteady.The lower velocity of the convective wind,the stronger thermal blooming.And especially which of the velocity of 1 m/s is the strongest and aberration of whose far field spot is the most severe.The unsteady property of thermal blooming is more visible as the velocity is lower.For example,thermal blooming at the velocity of 1 m/s is still changing in 5 s,but those at the 5 m/s or 10 m/s have trended to steady state after 3 s.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2010年第6期1569-1573,共5页
Chinese Journal of Lasers
