摘要
对超声速冷流条件下用于超燃冲压发动机的凹腔火焰稳定器的自激振荡特性进行研究.采用混合RANS/LES方法对非定常流场进行数值模拟,考虑了凹腔的长深比和后缘角度两个关键参数.混合RANS/LES方法很好的捕捉到流场非定常大尺度结构并揭示了凹腔自由剪切层的演化过程.对凹腔压力振荡历程进行幅频分析,所得到的频率和理论分析结果与文献计算结果符合的很好.结果表明,凹腔的长深比和后缘角度对凹腔自激振荡特性都有很大的影响.随着凹腔长深比的减小,振荡能量趋于集中到某些频率对应的振荡模式上.随着凹腔后缘倾角的减小,大部分频率对应的振荡很快的被削弱;相对于陡后缘凹腔,小角度后缘凹腔只有较高频率对应的振荡模式存在.
Self-sustained oscillation of supersonic cold flowover cavities of scramjets is investigated.Unsteady flowfields are calculated by hybrid RANS/LES method.The key cavity parameters,cavity aft wall angle andthe ratio of cavitylengthto depth,are considered.The hybrid model captures the large scale unsteady characteristics and reveals the evolution process of cavityfree shearlayer.Pressure fluctuation spectra agree well with theoretical prediction.The hybrid RANS/LES data indicate that both cavity shape and size have significant effects on oscillation.Asthe ratio of cavitylengthto depth decreases,the oscillations tend to concentrate on several modes,and the frequency of maximumoscillation amplitude shifts to higher values.Most oscillations are greatly attenuate as the cavity aft wall angle decreases.Compared with a steep aft wall cavity,only highfrequency mode remains inthe cavity with small aft wall angle.
出处
《计算物理》
EI
CSCD
北大核心
2007年第5期591-597,共7页
Chinese Journal of Computational Physics
基金
NSFC under Grant(No.90505009)
