The objective of this study is to demonstrate that strongly impinging jets-in-crossflow (JIC) will result in a counter flowing jet that will probably be unsteady. This numerical study was conducted in a 360^o (complete cylindrical duct) computational domain using a steady-state Reynolds-Averaged Navier Stokes, RANS, and time-dependent URANS at various momentum-flux ratios J. Asymmetry in a steady-state RANS solution is very likely to be an indication of the flow’s instability and unsteadiness. RANS predictions clearly show asymmetry in cases of strongly impinging jets. RANS solutions show that steady-state solutions are not appropriate if the flow is, or is suspected to be, unsteady. RANS and URANS solutions for computational domains <360^o will require boundary conditions at the edges of the computational domain and will not correctly represent the flow if it is unsteady even if the RANS solution converges. The results of this study are consistent with, and extend, the experimental and numerical results published earlier that were motivated by mixing in gas turbine combustors.

这项研究的目的是证明强力横流射流（JIC）将导致逆流射流，该射流可能不稳定。此数值研究是在360 ^o（完整圆柱管）计算域中使用稳态雷诺平均Navier Stokes，RANS和时间相关的URANS在各种动量通量比下进行的。稳态RANS解决方案中的不对称性很可能是表明流动不稳定和不稳定的迹象。RANS的预测清楚地表明了在强射流情况下的不对称性。兰斯解决方案表明，如果流量不稳定或怀疑不稳定，则稳态解决方案不合适。用于计算域<360 ^o的RANS和URANS解决方案将需要在计算域的边界处设置边界条件，并且即使RANS解决方案收敛，即使不稳定也不能正确表示流量。这项研究的结果与早期发表的实验和数值结果一致，并得到了扩展，这些结果是由于在燃气轮机燃烧器中混合而产生的。