Comment on: In vitro prediction of the lower/upper-critical biofluid flow choking index and in vivo demonstration of flow choking in the stenosis artery of the animal with air embolism

In a recent paper published in Physics of Fluids, Sanal Kumar et al. present a model of transonic compressible flows based on ideal gas theory that is irrelevant to biofluid flow and there are flaws in the general reasoning. In addition, the experimental attempts do not show any evidence of supersonic flow and do not provide any support for the flawed theory. In this Comment, I discuss why this paper and other very similar ones by the same group of authors and published in a short time frame (in Physics of Fluids and other journals) should have been retracted.