High Reynolds transonic ideal and non-ideal gas flows around a smooth circular cylinder are investigated by means of Large Eddy Simulations over a range of Mach numbers encompassing the drag divergence. The global aerodynamic performance of the cylinder in both air and a dense vapor are compared, as well as the influence of the thermodynamic behavior of the working fluid on the wake development. The drag divergence is delayed in the dense vapor flow compared to air, and the overall pressure drag is increased due to the lower back pressure. Loss generation mechanisms are also studied via entropy production in the boundary layer and by means of a loss breakdown analysis commonly used in turbomachinery. The specific entropy production rate is found to be lower in the dense gas flow compared to air. Finally, the momentum loss coefficient is reduced upon suppressing unsteady transonic vortex shedding.

通过大涡模拟在包含阻力发散的马赫数范围内研究围绕光滑圆柱体的高雷诺跨音速理想和非理想气体流动。比较了气缸在空气和浓蒸汽中的整体空气动力学性能，以及工作流体的热力学行为对尾流发展的影响。与空气相比，稠密蒸汽流中的阻力发散被延迟，并且由于背压较低，总体压力阻力增加。还通过边界层中的熵产生以及涡轮机械中常用的损失分解分析来研究损失产生机制。发现与空气相比，稠密气流中的比熵产率较低。最后，在抑制非定常跨音速涡旋脱落的同时，动量损失系数减小。