Noise Prediction for Increasingly Complex Jets. Part II: Applications
Noise Prediction for Increasingly Complex Jets. Part II: Applications
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日益复杂的喷气机的噪声预测。
DOI：
10.1260/1475472054771385
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发表时间：
2005
影响因子：
1
通讯作者：
M. Strelets
中科院分区：
文献类型：
--
作者：
M. Shur;P. Spalart;M. Strelets
在第一部分（参考文献1）中描述的数值系统适用于增加难度的各种情况，并朝着对客机发动机进行完全模拟的方向发展。网格有大约一百万个点。在许多情况下，该系统在指向性和频谱方面都满足2-3 dB的精度目标，直到斯特劳哈尔数约为1.5。喷流马赫数从0.3变化到稍超音速，膨胀不足，产生激波单元，大大增加了侧线噪声。对于加热射流，正确地再现了声学马赫数和温度之间的交叉效应。射流放置在一个共同流动的流与速度高达60%的射流的研究，并发现维持自然过渡没有不稳定的强迫，噪音的趋势是正确的。最后，通过改变来流条件来增加“合成人字形”，并发现可以降低低频噪声，同时增加中频噪声。总共，约十五个有意义的不同的情况下，并进行定量比较的方向/频率空间没有重大故障。大涡模拟方法的主要限制仍然是其频率上限。
The numerical system described in Part I (Ref. 1) is applied to a variety of cases which increase difficulty, and progress in the direction of the complete simulation of an airliner engine. The grids have on the order of 1 million points. In many cases, the system meets the 2–3 dB accuracy target both in terms of directivity and of spectrum, up to a Strouhal number of about 1.5. The jet Mach number is varied from 0.3 to slightly supersonic with under-expansion, generating shock cells and greatly increasing side-line noise. For heated jets, the cross-effect between the acoustic Mach number and the temperature is correctly reproduced. Jets placed in a co-flowing stream with velocity up to 60% of the jet's are studied and found to sustain natural transition without unsteady forcing; the noise trends are correct. Finally, “synthetic chevrons” are added by altering the inflow conditions, and found to reduce low-frequency noise while increasing mid-frequency noise. In total, about fifteen meaningfully different cases are presented, and subjected to quantitative comparisons over the direction/frequency space without major failure. The principal limitation of the large-eddy-simulation approach remains its upper limit on frequency.