论文标题
径向对称的非异类Euler流动:持续爆炸,正压
Radially Symmetric Non-isentropic Euler flows: continuous blowup with positive pressure
论文作者
论文摘要
古德利(Guderley)1942年在径向冲击波上的工作提供了自相似的欧拉(Euler)流的案例,表现出对原发性(未分化)流量变量的爆炸的爆炸:一种融合的冲击波侵入静态区域,并且在倒塌时立即唤醒的速度和压力在其立即唤醒中无扣。但是,这些解决方案具有边界线的物理性:由于那里的温度消失,压力在静止区域内消失。合理的是,缺乏上游的反压有利于大速度,并具有较大的幅度。因此,基于古德利(Guderley)的原始解决方案,尚不清楚是否是负责爆炸的零压力区域。同样,它也适用于描述径向腔流的自相似的欧拉流,首先由Hunter(1960)分析。 最近的作品表明,简化的等温模型和等渗模型在存在严格正压场的情况下接收连续的爆炸解决方案。在这项工作中,我们将此结论扩展到完整的Euler系统。所考虑的解决方案是径向自相似的流,其中连续波聚焦和炸毁。我们在爆炸之外传播了解决方案,并从数值上观察到在某些情况下会在塌陷时产生膨胀的球形冲击波。所得的解决方案具有异常的特性,即在两个被冲击隔开的区域中的每个区域中的每个区域中都具有等感。我们最终验证了这些是可接受的全球弱解决方案,可用于完整的多D压缩欧拉系统。
Guderley's 1942 work on radial shock waves provides cases of self-similar Euler flows exhibiting blowup of primary (undifferentiated) flow variables: a converging shock wave invades a quiescent region, and the velocity and pressure in its immediate wake become unbounded at time of collapse. However, these solutions are of border-line physicality: the pressure vanishes within the quiescent region due to vanishing temperature there. It is reasonable that the lack of upstream counter-pressure is conducive to large speeds, with concomitant large amplitudes. Based on Guderley's original solutions it is therefore unclear if it is the zero-pressure region that is responsible for blowup. The same applies to self-similar Euler flows describing radial cavity flow, first analyzed by Hunter (1960). Recent works have shown that the simplified isothermal and isentropic models admit continuous blowup solutions in the presence of a strictly positive pressure field. In this work we extend this conclusion to the case of the full Euler system. The solutions under consideration are radial self-similar flows in which a continuous wave focuses and blows up. We propagate the solutions beyond blowup and observe numerically that there are cases where an expanding spherical shock wave is generated at collapse. The resulting solution has the unusual property that the flow is isentropic in each of the two regions separated by the shock. We finally verify that these are admissible global weak solutions to the full, multi-d compressible Euler system.